CIE iGCSE Co-Ordinated Science P1.2 Motion Exam Style Questions Paper 3
Question
A person climbs a mountain.
(a) The person is exposed to infrared and ultraviolet radiation from the Sun.
Infrared and ultraviolet radiation are part of the electromagnetic spectrum.
(i) Fig. 3.1 shows an incomplete electromagnetic spectrum.
On Fig. 3.1, write infrared and ultraviolet in their correct places.
(ii) Ultraviolet waves travel at 300 000 000 m / s in a vacuum.
State the speed of infrared waves in a vacuum.
(b) The person makes a loud sound and then hears an echo.
State what is meant by an echo.
(c) The person takes a photograph with a camera.
The camera contains a thin converging lens.
Fig. 3.2 shows an incomplete ray diagram for a thin converging lens forming an image.
(i) State the name of the points labelled F on Fig. 3.2.
(ii) On Fig. 3.2:
• draw a line to complete the path of ray 2
• draw the image formed
• label the image.
(d) The person drops the camera from the top of the mountain. The camera falls down the mountain.
Fig. 3.3 shows the distance–time graph for the motion of the camera over the first 6.0 s
Use Fig. 3.3 to determine the average speed of the camera over 6.0 s.
▶️Answer/Explanation
Ans : 3(a)(i)
infrared correct ;
ultraviolet correct ;
3(a)(ii) 300 000 000 (m / s) ;
3(b) the reflection of sound ;
3(c)(i) principal focus / focal point ;
3(c)(ii) horizontal line drawn from lens to intersect with ray 1 ;
inverted (labelled) arrow for image ;
3(d) total distance 180m ;
evidence of speed = distance ÷ time / 180 ÷ 6.0 ;
30 (m/ s) ;
Question
(a) A rock that travels through space and hits the Earth’s surface is called a meteorite.
Fig. 3.1 shows a speed–time graph for a meteorite as it:
• travels through space
• slows down through the Earth’s atmosphere
• hits the Earth’s surface.
i) State the maximum speed of the meteorite.
(ii) State the time at which the meteorite hits the surface of the Earth.
(iii) State the name of the force that causes the meteorite to slow down through the Earth’s atmosphere.
(b) (i) The weight of the meteorite is 3.3 × 10$^{8}$ N.
The gravitational force on unit mass, g, is 10 N/kg.
Calculate the mass of the meteorite.
(ii) The volume of the meteorite is 4200 m$^{3}$ .
Use your answer to (b)(i) to calculate the density of the meteorite.
State the units of your answer.
(c) The meteorite contains large amounts of iron.
Magnets are made from iron. A piece of iron can be magnetised by stroking it with a magnet.
Describe one other method of magnetisation.
(d) The nuclide notations for two iron isotopes are shown.
(i) Complete the sentence to define the term isotope.
Isotopes are atoms of the same element which have the same ………………………………….
number but a different …………………………………. number.
(ii) State the number of neutrons in an atom of isotope A and in an atom of isotope B.
isotope A ……………………………
isotope B …………………………..
▶️Answer/Explanation
Ans : 3(a)(i) 30 000 (m/ s) ;
3(a)(ii) 20 (s) ;
3(a)(iii) friction / air resistance ;
3(b)(i) evidence of mass = weight / g or 3.3 10$^{8}$/10 ;
mass = 3.3×10$^{7}$(kg) ;
3(b)(ii) evidence of density = mass / volume (in any form) or 3.3×10$^{7}$ ÷ 4200 ;
7900 ;
kg/m$^{3}$;
3(c) place in solenoid / coil and pass (d.c.) electric current through solenoid / coil or
place in direction of Earth’s magnetic field and hammer it (gently) ;
3(d)(i) proton / atomic and
nucleon / mass ;
3(d)(ii) isotope A = 28 neutrons and isotope B = 30 neutrons ;
Question
(a) A student investigates the motion of smoke particles in air using a microscope.
Fig. 12.1 shows the apparatus the student uses.
The student sees the smoke particles moving in random directions.
This movement is caused by collisions between smoke particles and moving molecules in the air.
Fig. 12.2 shows the path of one smoke particle observed by the student.
State the name given to the motion of the smoke particles observed by the student.
……………………………………………………………………………………………………………………………
(b) The lamp in Fig. 12.1 has a current of 0.40A in it when the potential difference across it is 3.0V.
Calculate the resistance of the lamp.
resistance = ……………………………………………… Ω
(c) The microscope in Fig. 12.1 contains lenses.
Fig. 12.3 shows a ray of light from the top of a smoke particle passing through a thin converging lens.
(i) Draw a second ray from the top of the smoke particle to locate the position of the top of the image.
Label the top of the image with the letter I.
(ii) On Fig. 12.3, label the principal focus of the lens with the letter F.
(iii) On Fig. 12.3, use a double headed arrow (↔) or (↕) to show the focal length of the lens.
(iv) Circle the two correct words or phrases that describe the image.
diminished enlarged inverted same size upright
▶️Answer/Explanation
Ans: 12(a) Brownian (motion) ;
12(b) R= V / I (in any form) or 3.0 / 0.4 ;
= 7.5 (Ω) ;
12(c)(i) second line through centre of lens ;
image labelled I ;
12(c)(ii) principal focus correctly labelled ;
12(c)(iii) focal length correctly shown ;
12(c)(iv) diminished ;
inverted ;
Question
(a) (i) Fig. 3.1 shows a skier standing on the snow.
When she stands on the snow without her skis, she sinks into the snow.
When she wears her skis, she can stand on the snow without sinking.
Explain these observations.
(ii) The skier makes a sound near a high wall.
The sound travels through the air as a wave.
The skier hears an echo.
State what happens to the sound wave at the high wall to cause an echo to be heard.
(b) Fig. 3.2 shows the forces acting on the skier on level snow when she is travelling in a snowmobile.
(i) State which force, J, K, L or M, is the weight of the snowmobile and skier.
(ii) State which force, J, K, L or M, is the friction force acting on the snowmobile.
(c) Fig. 3.3 shows the speed–time graph for the motion of the skier.
(i) State the maximum speed of the skier.
speed = …………………………………………. m / s
(ii) The skier is accelerating during the first 20 s of her journey.
Describe how the graph shows that the skier is accelerating.
(iii) Show that the distance travelled by the skier during the first 20 s is 50 m.
(d) The skier is exposed to ultraviolet radiation from the Sun.
Ultraviolet radiation is a form of ionising radiation.
Describe one danger to humans of being exposed to large quantities of ultraviolet radiation.
▶️Answer/Explanation
Ans : 3(a)(i) skis increase surface area ;
pressure is less with skis ; ORA
3(a)(ii) sound wave is reflected ;
3(b)(i) L ;
3(b)(ii) K ;
3(c)(i) 5 (m / s) ;
3(c)(ii) line has a slope / gradient ;
3(c)(iii) area under graph or ½ × 5 × 20 ;
3(d) skin cancer ;
Question
(a) A spacecraft carrying an astronaut travels 384 000 km from the Earth to the Moon in 78 hours.
Calculate the average speed of the spacecraft in km / s.
average speed = ………………………………………… km / s
(b) The mass of the astronaut on the Earth is 90 kg.
(i) Calculate the weight of the astronaut on the Earth.
The gravitational force on unit mass, g, is 10 N / kg.
weight = …………………………………………….. N
(ii) State the mass of the astronaut on the Moon.
mass = ……………………………………………. kg
(c) (i) The astronaut communicates with Earth using radio waves.
Fig. 3.1 shows an incomplete electromagnetic spectrum.
Write radio waves in the correct position in Fig. 3.1.
(ii) Explain why it is not possible for the astronaut to communicate with Earth using sound waves.
(d) The astronaut collects a lump of moon rock.
The rock contains iron-60, a radioactive isotope.
(i) State the meaning of the term isotope.
(ii) Iron-60 decays by the emission of β-particles.
Complete the sentences to describe the nature of β-particles.
β-particles are identical in nature to ………………………………… .
β-particles have a single ………………………………… charge.
▶️Answer/Explanation
Ans : 3(a) 78 hours = 78 × 3600 = 280 800 seconds ;
speed = distance / time (in any form) or 384 000 / 280 800 ;
= 1.37 (km / s) ;
3(b)(i) weight = mass × g (in any form) or 90 × 10 ;
= 900 (N) ;
3(b)(ii) 90 (kg) ;
3(c)(i) radio (waves) in right hand box ;
3(c)(ii) sound waves need a medium / sound waves do not travel through a vacuum ;
3(d)(i) atoms of the same element that have different numbers of neutrons ;
OR
atoms which have the same number of protons and different numbers of neutrons ;
OR
atoms which have the same atomic number but different mass number ;
3(d)(ii) electrons ;
negative ;
Question
(a) An oil tanker is carrying petroleum.
Petroleum is a non-renewable energy source.
Identify the energy sources in Table 12.1 as renewable or non-renewable by placing a tick (3) for each one in the correct column.
One has been done for you.
(b) Fig. 12.1 shows a speed–time graph for the oil tanker.
The graph is divided into sections P, Q, R and S.
(i) State a section of the graph (P, Q, R or S) when the oil tanker is travelling at a constant speed and state this speed.
section ………………………………….
speed …………………………………. m / s
(ii) State the section of the graph (P, Q, R or S) when the oil tanker has the greatest acceleration.
Explain your answer.
section ………………………………….
explanation …………………………………………………………………………
(iii) Calculate the distance travelled by the oil tanker during section P.
distance = …………………………………………….. m
(c) The captain of the oil tanker uses a telescope to look at another ship.
The telescope uses a converging lens to focus the light and form an image of the other ship.
Fig. 12.2 shows two parallel light rays passing through a convex lens.
(i) Complete the light rays in Fig. 12.2 to show how the light rays are focused by the lens at point F.
(ii) State the name of point F.
(d) Fig. 12.3 shows a wave similar to a water wave on the surface of the sea.
(i) State which letter, A, B, C, D or E, is the amplitude of the wave.
letter ………………..
(ii) State which letter, A, B, C, D or E, is the wavelength of the wave.
letter ………………..
▶️Answer/Explanation
Ans : 12(a) 
2 or 3 correct ;
4 correct ;
12(b)(i) section Q and 1 (m / s) OR
section S and 5 (m / s) ;
12(b)(ii) section R AND
greatest gradient ;
12(b)(iii) area under graph or 1/2 × 1 × 300 ;
150 (m) ;
12(c)(i) both rays meet at F ;
12(c)(ii) principal focus ;
12(d)(i) B ;
12(d)(ii) E ;
Question
(a) Fig. 3.1 shows four forces acting on a submarine. The submarine is moving underwater at a constant speed.
State which force A, B, C or D is the weight of the submarine.
▶️Answer/Explanation
Answer: C
Explanation: The weight of the submarine is the force due to gravity acting downward. In the diagram, force C is directed downward, indicating that it represents the weight of the submarine.
(b) The submarine travels 36 km in 2 hours. Calculate the speed of the submarine in m/s.
▶️Answer/Explanation
Answer: 5 m/s
Explanation:
- Convert 36 km to meters: \( 36 \text{ km} = 36,000 \text{ m} \).
- Convert 2 hours to seconds: \( 2 \text{ hours} = 2 \times 60 \times 60 = 7,200 \text{ s} \).
- Calculate speed using the formula \( \text{speed} = \frac{\text{distance}}{\text{time}} \): \( \text{speed} = \frac{36,000}{7,200} = 5 \text{ m/s} \).
(c) The submarine is powered by a small nuclear reactor. Ionising radiation is released in the reactor. The reactor must be shielded to protect the crew from this radiation.
(i) State how exposure to ionising radiation can affect the human body.
▶️Answer/Explanation
Answer: Cancer / cell mutation
Explanation: Ionising radiation can damage the DNA in cells, leading to mutations that may cause cancer or other harmful effects on the body.
(ii) Suggest a material which can be used to shield a nuclear reactor and stop \(\alpha\)-radiation and \(\beta\)-radiation escaping.
▶️Answer/Explanation
Answer: Lead
Explanation: Lead is a dense material that is effective at blocking \(\alpha\) and \(\beta\) radiation due to its high atomic number and density.
(d) Plutonium-239 (Pu-239) is the nuclear fuel used by the submarine. Pu-239 has a half-life of 24,000 years. A small sample of Pu-239 has a mass of 1.0 g. Calculate the mass of Pu-239 remaining after 96,000 years.
▶️Answer/Explanation
Answer: 0.0625 g
Explanation:
- Determine the number of half-lives in 96,000 years: \( \frac{96,000}{24,000} = 4 \) half-lives.
- Calculate the remaining mass after each half-life: \( 1.0 \text{ g} \rightarrow 0.5 \text{ g} \rightarrow 0.25 \text{ g} \rightarrow 0.125 \text{ g} \rightarrow 0.0625 \text{ g} \).
(e) When it is under the water, the submarine uses a periscope to view a ship on the surface of the sea. Fig. 3.2 shows a simple periscope.
On Fig. 3.2, draw a ray of light from the ship to the observer’s eye to show what happens to the light ray as it passes through the periscope.
▶️Answer/Explanation
Answer: The light ray should reflect off the top mirror and then the bottom mirror before reaching the observer’s eye.
Explanation: In a periscope, light from the ship enters the top mirror, reflects downward to the bottom mirror, and then reflects into the observer’s eye. The ray should be drawn to show these two reflections.
Question
(a) Water vapour in the air over the sea comes from liquid water in the sea.
(i) State the name of the process by which liquid water in the sea forms water vapour in the air.
…………………………………………………………………………………………………………………….
(ii) Describe how the process named in (i) occurs. Use ideas about water molecules in your answer.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(b) Fig. 6.1 shows a boat moving at constant speed.
Four forces A, B, C and D act on the boat.
State the name of force C.
…………………………………………………………………………………………………………………….
(c) Fig. 6.2 shows a speed-time graph for the boat.
(i) Determine the speed of the boat.
speed = …………………………………………. m/s
(ii) Calculate the distance travelled by the boat in 200s.
distance = …………………………………………….. m
(d) Fig. 6.3 shows a wave similar to a water wave on the surface of the sea.
(i) Determine the wavelength of the wave.
wavelength = …………………………………………….. m
(ii) On Fig. 6.3, indicate with a double headed arrow (↕ or ↔) the amplitude of the wave.
(iii) The frequency of the wave is 0.08Hz.
Calculate how many wavefronts pass a fixed point in 25 seconds.
▶️Answer/Explanation
Ans: 6(a)(i) evaporation
6(a)(ii) fastest moving/most energetic molecules/particles ;
escape from surface ;
6(b) Weight ;
6(c)(i) 4.4 (m/s) ;
6(c)(ii) distance = speed × time (in any form symbols or words) or 4.4 × 200 or area under graph ;
880 (m) ;
6(d)(i) 8 (m) ;
6(d)(ii) amplitude correctly indicated ;
6(d)(iii) 2.0 ;
Question
(a) Fig. 9.1 shows a rocket about to be launched.
(i) The weight of the rocket is 8000000N.
When the rocket is launched, the upward force exerted by the rocket is 12000000N.
Calculate the resultant upward force on the rocket.
resultant force = …………………………………………….. N
(ii) Explain why the resultant force cannot be zero, when the rocket is launched.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(iii) The rocket travels 385000km from the Earth to the Moon in 75 hours.
Calculate the average speed of the rocket in km/ s.
speed = ………………………………………… km/s
(b) An astronaut on the rocket uses a telescope to view a star.
Fig. 9.2 shows a lens that is used in the telescope. Light rays from the star pass through the
lens and are focused at the principal focus.
(i) On Fig. 9.2, label the principal focus of the lens with the letter F.
(ii) On Fig. 9.2, draw a double headed arrow ( ↔ ) to indicate the focal length of the lens.
(iii) State the name of the process that occurs when light passes into the lens and the direction of the light changes.
…………………………………………………………………………………………………………………….
(c) The astronaut communicates with Earth using radio waves.
(i) Place radio waves in the correct place in the incomplete electromagnetic spectrum shown in Fig. 9.3.
Fig. 9.3
(ii) State which part of the electromagnetic spectrum has the greatest frequency.
…………………………………………………………………………………………………………………….
(iii) Explain why it is not possible for the astronaut to use sound waves to communicate directly with Earth.
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans: 9(a)(i) 4 000 000 (N) ;
9(a)(ii) rocket would not, move/take off ;
9(a)(iii) conversion of 75 hours to seconds / 270 000 s ;
speed = distance ÷ time or substituted distance ÷ time ;
speed = 1.43 (km/s) ;
9(b)(i) principal focus correctly identified ;
9(b)(ii) focal length correctly identified ;
9(b)(iii) refraction ;
9(c)(i)
9(c)(ii) $\gamma$- rays ;
9(c)(iii) there is no medium / there is a vacuum ;
no particles to transfer the vibrations (preventing sound from travelling) ;
Question
An astronomer observes a large meteorite, a rock from outer space. The astronomer uses a telescope which contains mirrors.
Fig. 12.1 shows the image of the meteorite seen in the mirror by the astronomer.
(a) Select two words or phrases from the list to describe the characteristics of an image formed by a single plane mirror.
▶️Answer/Explanation
The two characteristics of an image formed by a single plane mirror are:
- same size
- upright
(b) The meteorite enters the Earth’s atmosphere.
Fig. 12.2 is a speed-time graph for the meteorite as it approaches Earth.
(i) On Fig. 12.2, label with an S a point when the meteorite is slowing down.
▶️Answer/Explanation
The meteorite slows down when it experiences air resistance, which occurs after it reaches its maximum speed. Label a point on the graph where the speed starts to decrease.
S somewhere between 5 s and 12 s
(ii) State the form of energy lost by the meteorite as it slows down.
▶️Answer/Explanation
The meteorite loses kinetic energy as it slows down due to air resistance and friction with the atmosphere.
(iii) Use Fig. 12.2 to determine the maximum speed of the meteorite.
▶️Answer/Explanation
The maximum speed of the meteorite is 36,000 m/s, as indicated by the highest point on the speed-time graph.
(c) The mass of the meteorite is 22,500 kg. The density of the meteorite is 7500 kg/m3.
(i) Calculate the volume of the meteorite.
▶️Answer/Explanation
Using the formula: Volume = Mass ÷ Density,
Volume = 22,500 kg ÷ 7500 kg/m3 = 3.0 m3.
(ii) A scientist suggests that the meteorite contains metallic iron.
Suggest a simple way for the scientist to test for iron in an object found on Earth.
▶️Answer/Explanation
The scientist can use a magnet to test for the presence of iron. If the object is attracted to the magnet, it likely contains iron.
(d) The meteorite’s temperature is 1500°C when it falls into the sea. The meteorite loses thermal energy to the water.
(i) State the main method of thermal energy transfer from the meteorite into the water.
▶️Answer/Explanation
The main method of thermal energy transfer from the meteorite into the water is conduction, as the heat is transferred through direct contact between the meteorite and the water.
(ii) Some of the seawater evaporates.
Describe the process of evaporation in terms of the movement and energy of water molecules.
▶️Answer/Explanation
Evaporation occurs when the most energetic water molecules at the surface gain enough energy to escape into the air as gas. This process cools the remaining liquid as the higher-energy molecules leave.
(iii) The meteorite is a solid and the seawater is a liquid.
Draw more circles in the boxes in Fig. 12.3 to show the arrangement and separation of particles in a solid and in a liquid.
▶️Answer/Explanation
In a solid, particles are closely packed in a regular arrangement. In a liquid, particles are close together but not in a fixed arrangement, allowing them to move past each other.
Question
(a) Fig. 12.1 is a speed-time graph for an aircraft taking off.
(i) Calculate the distance travelled between t = 0 s and t = 25 s.
distance = …………………………………………….. m
(ii) On Fig. 12.1, identify a time when the aircraft has the greatest acceleration.
time = ……………………… s
explanation …………………………………………………………………………………………………………
(iii) State two types of energy gained by the aircraft as it accelerates and gains height after take-off.
1 ………………………………………………………… energy
2 ………………………………………………………… energy
▶️Answer/Explanation
(i) The distance travelled between t = 0 s and t = 25 s is 575 m.
Explanation: The area under the speed-time graph represents distance. For the first 25 seconds, the graph forms a triangle. The area of the triangle is calculated as:
Area = ½ × base × height = ½ × 25 s × 46 m/s = 575 m.
(ii) The greatest acceleration occurs between t = 0 s and t = 34 s.
Explanation: The steepest gradient on the speed-time graph indicates the greatest acceleration. This occurs during the initial phase of take-off.
(iii) The two types of energy gained by the aircraft are:
- Kinetic energy
- Gravitational potential energy
(b) Fig. 12.2 shows the four forces, A, B, C, and D, acting on the aircraft flying at a constant height and constant speed.
(i) Compare the forces B and D. Explain your answer.
(ii) State which force, A, B, C, or D, shows the weight of the aircraft.
force …………………………
(iii) The weight of the aircraft is 1 × 106 N.
Calculate the mass of the aircraft in kg.
The gravitational field strength g is 10 N/kg.
mass = ……………………………………………. kg
▶️Answer/Explanation
(i) Forces B and D are equal and opposite.
Explanation: Since the aircraft is flying at a constant height and constant speed, the forces acting on it must be balanced. Force B (thrust) and Force D (drag) are equal in magnitude but act in opposite directions.
(ii) The force that shows the weight of the aircraft is C.
Explanation: Weight acts vertically downward, and in the diagram, Force C represents the gravitational force (weight) acting on the aircraft.
(iii) The mass of the aircraft is 100,000 kg.
Explanation: Using the formula:
Weight = mass × gravitational field strength (g)
1 × 106 N = mass × 10 N/kg
Mass = 1 × 106 N / 10 N/kg = 100,000 kg.
Question
(a) A cyclist starts from rest and accelerates for 20 s. The cyclist then travels at a constant speed of 5 m/s for 90 s. Finally, the cyclist slows down and stops after a further 5 s.
(i) On the grid in Fig. 3.1, draw a speed-time graph for the cyclist’s journey.
▶️Answer/Explanation
The speed-time graph should have three sections:
- From 0 to 20 seconds: A straight line rising from (0, 0) to (20, 5) m/s, representing constant acceleration.
- From 20 to 110 seconds: A horizontal line at 5 m/s, representing constant speed.
- From 110 to 115 seconds: A straight line falling from (110, 5) to (115, 0) m/s, representing constant deceleration.
(ii) Calculate the distance travelled when the cyclist is travelling at constant speed.
▶️Answer/Explanation
Distance = Speed × Time
Speed = 5 m/s
Time = 90 s
Distance = 5 m/s × 90 s = 450 m
(b) Energy from the Sun heats the black saddle of the bicycle.
(i) State the method of energy transfer between the Sun and the Earth.
▶️Answer/Explanation
The method of energy transfer between the Sun and the Earth is radiation.
(ii) Name the part of the Sun’s electromagnetic spectrum that is responsible for heating the saddle.
▶️Answer/Explanation
The part of the Sun’s electromagnetic spectrum responsible for heating the saddle is infrared.
(iii) The Sun also heats up the air in the bicycle tyres. This causes the pressure of the air in the tyres to increase. Describe, in terms of the motion of the air molecules, why the pressure of the air in the tyres increases as the temperature of the air increases.
▶️Answer/Explanation
As the temperature of the air increases, the kinetic energy of the air molecules increases. This causes the molecules to move faster and collide more frequently with the walls of the tyre, resulting in an increase in pressure.
(c) Fig. 3.2 shows a metal nut on the bicycle which is difficult to unscrew.
Fig. 3.3 shows two spanners A and B.
Explain why it is easier to use spanner B to unscrew the nut rather than spanner A.
▶️Answer/Explanation
Spanner B is longer than spanner A. The turning effect (moment) of a force is calculated as Moment = Force × Distance from the pivot. Since spanner B has a longer handle, it provides a greater distance from the pivot, allowing a smaller force to produce the same turning effect, making it easier to unscrew the nut.
(d) The cyclist uses a plane mirror placed on his bicycle to see behind him.
State two characteristics of an image seen in a plane mirror.
▶️Answer/Explanation
Two characteristics of an image seen in a plane mirror are:
- The image is upright.
- The image is laterally inverted (left and right are reversed).
Question
(a) Fig. 6.1 shows the speed-time graph for the journey of a train travelling between two stations.
(i) Use letters from the graph in Fig. 6.1 to identify the two stations on the train’s journey.
▶️Answer/Explanation
Answer: A and D
Explanation: The graph shows the train starting at station A (where the speed is zero) and ending at station D (where the speed returns to zero).
(ii) On Fig. 6.1, label with a cross \(X\) a part of the journey when the train is accelerating.
▶️Answer/Explanation
Answer: X anywhere between A and B or between C and D
Explanation: The train is accelerating when the speed is increasing, which occurs between A and B and between C and D.
(iii) Use Fig. 6.1 to calculate the total distance travelled by the train on this journey.
▶️Answer/Explanation
Answer: 2500 m
Explanation: The total distance travelled can be calculated by finding the area under the speed-time graph. The graph can be divided into three sections: a triangle, a rectangle, and another triangle. The area of the first triangle (A to B) is \( \frac{1}{2} \times 1000 \times 10 = 5000 \) m, the area of the rectangle (B to C) is \( 1000 \times 10 = 10000 \) m, and the area of the second triangle (C to D) is \( \frac{1}{2} \times 1000 \times 10 = 5000 \) m. Adding these areas together gives a total distance of 2500 m.
(b) Fig. 6.2 shows the forces acting on the train when it travels at a constant speed.
(i) State which force, P, Q, R or S, is the weight of the train.
▶️Answer/Explanation
Answer: R
Explanation: The weight of the train acts vertically downward, which is represented by force R in the diagram.
(ii) Compare the magnitude and the direction of forces Q and S when the train is travelling at a constant speed.
▶️Answer/Explanation
Answer: Equal (magnitude); opposite directions
Explanation: When the train is travelling at a constant speed, the forces acting on it are balanced. Therefore, the magnitude of force Q (driving force) is equal to the magnitude of force S (frictional force), but they act in opposite directions.
Question
(a) Fig. 9.1 shows an aircraft on a runway.
Use the letters A, B, C or D to complete the sentences. Each letter may be used once, more than once or not at all.
When the aircraft is at rest on the runway, force A is equal to force ………….. and also force B is equal to force ………….. .
When the aircraft starts to accelerate along the runway, forces ………….. and ………….. are unbalanced.
▶️Answer/Explanation
When the aircraft is at rest on the runway, force A is equal to force C and also force B is equal to force D.
When the aircraft starts to accelerate along the runway, forces B and D are unbalanced.
(b) Fig. 9.2 shows the speed-time graph for the aircraft during part of its flight when it is travelling at constant height.
(i) Label with a cross (X) a part of the flight when the aircraft is accelerating.
(ii) State which section of the graph shows the aircraft travelling with no acceleration. Explain your answer.
▶️Answer/Explanation
(i) The part of the graph where the speed is increasing (e.g., the initial upward slope) should be labeled with a cross (X).
(ii) The section of the graph where the speed is constant (e.g., the horizontal line) shows the aircraft travelling with no acceleration. This is because the speed is not changing, indicating that the forces are balanced and there is no acceleration.
(c) The aircraft fuel is a non-renewable energy source obtained from petroleum.
(i) Identify the form of energy stored in aircraft fuel.
(ii) Name two renewable energy sources.
▶️Answer/Explanation
(i) The form of energy stored in aircraft fuel is chemical energy.
(ii) Two renewable energy sources are solar energy and wind energy.
Question
(a) Fig. 3.1 shows a speed–time graph for a bus journey.
(i) Draw an X on the graph where the bus is not moving.
▶️Answer/Explanation
Solution:
The bus is not moving when the speed is 0 m/s. On the graph, this occurs at the points where the speed-time graph intersects the time axis (i.e., at t = 0 s and t = 160 s). Therefore, an X should be placed at these points.
X at (0,0) or (160,0)
(ii) Calculate the distance travelled by the bus in the first 60 s of the journey.
▶️Answer/Explanation
Solution:
The distance travelled can be calculated by finding the area under the speed-time graph for the first 60 seconds. The graph shows a triangle from 0 to 60 seconds with a base of 60 seconds and a height of 20 m/s.
The area of a triangle is given by:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
Substituting the values:
\[ \text{Area} = \frac{1}{2} \times 60 \times 20 = 600 \text{ m} \]
Therefore, the distance travelled by the bus in the first 60 seconds is 600 meters.
600 m
(b) The bus has a mass of 5000 kg.
(i) Calculate the weight of the bus. The gravitational field strength g is 10 N / kg.
▶️Answer/Explanation
Solution:
The weight of an object is calculated using the formula:
\[ \text{Weight} = \text{mass} \times \text{gravitational field strength} \]
Given that the mass of the bus is 5000 kg and the gravitational field strength \( g \) is 10 N/kg:
\[ \text{Weight} = 5000 \times 10 = 50000 \text{ N} \]
Therefore, the weight of the bus is 50000 N.
50000 N
(ii) State the source of the gravitational field acting on the bus.
▶️Answer/Explanation
Solution:
The source of the gravitational field acting on the bus is the Earth.
Earth
(c) Fig. 3.2 shows the forces A, B, C and D as the bus moves forward at constant speed.
(i) Force B is increased. Describe how this affects the motion of the bus.
▶️Answer/Explanation
Solution:
If Force B is increased, the bus will accelerate because the resultant force acting on the bus will no longer be zero. The bus will start to move faster in the direction of the increased force.
The bus accelerates.
(ii) Force B is 500000 N. Force D is 100000 N. Calculate the resultant force of these two forces.
▶️Answer/Explanation
Solution:
The resultant force is calculated by subtracting Force D from Force B:
\[ \text{Resultant Force} = \text{Force B} – \text{Force D} = 500000 – 100000 = 400000 \text{ N} \]
Therefore, the resultant force is 400000 N.
400000 N
(d) The driver changes a wheel. Fig. 3.3 shows a wrench being used to loosen a wheel nut.
The driver applies a force of 1000 N on the wrench. Calculate the moment of this force on the wheel nut.
▶️Answer/Explanation
Solution:
The moment of a force is calculated using the formula:
\[ \text{Moment} = \text{Force} \times \text{Perpendicular Distance} \]
Given that the force applied is 1000 N and the perpendicular distance is 45 cm (which is 0.45 m):
\[ \text{Moment} = 1000 \times 0.45 = 450 \text{ Nm} \]
Therefore, the moment of the force on the wheel nut is 450 Nm.
450 Nm
Question
(a) A skydiver jumps from an aircraft high above the ground. Fig. 3.1 shows the speed–time graph of his descent.
Use the graph in Fig. 3.1 to calculate how far the skydiver falls from time \( t = 0 \, \text{s} \) to \( t = 10 \, \text{s} \).
▶️Answer/Explanation
Answer: 250 m
Explanation: The distance fallen by the skydiver can be calculated by finding the area under the speed-time graph from \( t = 0 \, \text{s} \) to \( t = 10 \, \text{s} \). The graph forms a triangle during this time interval. The area of a triangle is given by: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \] Here, the base is 10 seconds, and the height is 50 m/s. Therefore: \[ \text{Distance} = \frac{1}{2} \times 10 \, \text{s} \times 50 \, \text{m/s} = 250 \, \text{m} \]
(b) When the skydiver opens the parachute at \( t = 10 \, \text{s} \), his speed decreases. Name the force that causes this decrease in speed.
▶️Answer/Explanation
Answer: Air resistance (or friction)
Explanation: When the skydiver opens the parachute, the surface area exposed to air increases, leading to an increase in air resistance (or friction). This force opposes the motion of the skydiver, causing the speed to decrease.
(c) The skydiver has a mass of 85 kg. His weight is 850 N.
(i) State the size of the upwards force on the skydiver at \( t = 80 \, \text{s} \). Explain your answer.
▶️Answer/Explanation
Answer: 850 N
Explanation: At \( t = 80 \, \text{s} \), the skydiver is descending at a constant speed, which means the forces acting on him are balanced. The upwards force (air resistance) must be equal to the downwards force (weight) to maintain this constant speed. Therefore, the upwards force is 850 N.
(ii) State the value of the gravitational field strength \( g \) that is used to determine the weight of the skydiver in (c). Give the units of \( g \).
▶️Answer/Explanation
Answer: 10 N/kg
Explanation: The gravitational field strength \( g \) is calculated using the formula: \[ g = \frac{W}{m} \] where \( W \) is the weight and \( m \) is the mass. Given that the weight is 850 N and the mass is 85 kg: \[ g = \frac{850 \, \text{N}}{85 \, \text{kg}} = 10 \, \text{N/kg} \] The units of \( g \) are newtons per kilogram (N/kg).
(d) The skydiver lands in a pit full of sand. The dimensions of the sand pit are shown in Fig. 3.2.
The density of sand is \( 1800 \, \text{kg/m}^3 \). Calculate the mass of the sand in the pit.
▶️Answer/Explanation
Answer: 27000 kg
Explanation: The mass of the sand can be calculated using the formula: \[ \text{mass} = \text{density} \times \text{volume} \] First, calculate the volume of the sand pit: \[ \text{Volume} = \text{length} \times \text{width} \times \text{height} = 6.0 \, \text{m} \times 5.0 \, \text{m} \times 0.5 \, \text{m} = 15 \, \text{m}^3 \] Then, calculate the mass: \[ \text{mass} = 1800 \, \text{kg/m}^3 \times 15 \, \text{m}^3 = 27000 \, \text{kg} \]
Question
(a) The diagram in Fig. 2.1 shows part of the water cycle.
Clouds form above the sea and rain falls from the clouds. Clouds are made up of very small drops of liquid water.
The letters P, Q, and R show locations where physical changes happen in the water cycle.
(i) Use the letters P, Q, and R to complete Table 2.1.
Each letter may be used once, more than once, or not at all.
| Description of change | Location |
|---|---|
| Water vapour condenses | |
| Liquid water gains kinetic energy | |
| Water molecules move closer together | |
| Water evaporates |
▶️Answer/Explanation
Answer:
| Description of change | Location |
|---|---|
| Water vapour condenses | Q |
| Liquid water gains kinetic energy | R |
| Water molecules move closer together | Q |
| Water evaporates | P |
Explanation:
– Water vapour condenses at location Q, where the water vapour in the clouds turns into liquid water.
– Liquid water gains kinetic energy at location R, where the water is heated and gains energy to evaporate.
– Water molecules move closer together at location Q, where condensation occurs, causing the molecules to come closer.
– Water evaporates at location P, where the liquid water turns into water vapour due to heat energy.
(ii) Explain why the changes P, Q, and R are physical changes.
▶️Answer/Explanation
Answer:
The changes P, Q, and R are physical changes because they involve changes in the state of water (solid, liquid, gas) without altering the chemical composition of the water molecules. In physical changes, no new substances are formed, and the process is reversible. Explanation:
– Evaporation (P): Water changes from liquid to gas, but the chemical structure of H2O remains the same.
– Condensation (Q): Water changes from gas to liquid, but the chemical structure remains unchanged.
– Gaining kinetic energy (R): The water molecules gain energy, but the chemical composition of the water remains the same.
(b) Carbon dioxide in the air dissolves in rainwater. This causes the rainwater to become slightly acidic.
(i) Water is neutral. State the pH value of water.
▶️Answer/Explanation
Answer:
The pH value of water is 7. Explanation:
Water is considered neutral because it has a pH of 7, which is neither acidic nor basic.
(ii) Suggest a pH value of rainwater.
▶️Answer/Explanation
Answer:
The pH value of rainwater is less than 7, typically around 5.6. Explanation:
Rainwater becomes slightly acidic due to the dissolution of carbon dioxide, forming carbonic acid, which lowers the pH below 7.
(c) Complete the word equation for the neutralisation reaction between an acid and a base.
acid + base → ________ + ________
▶️Answer/Explanation
Answer:
acid + base → salt + water Explanation:
In a neutralisation reaction, an acid reacts with a base to produce a salt and water.
(d) Table 2.2 shows some oxides. It also shows whether they are acidic or basic.
| Oxide | Acidic or Basic |
|---|---|
| Carbon dioxide | Acidic |
| Chlorine oxide | Acidic |
| Magnesium oxide | Basic |
| Phosphorus oxide | Acidic |
| Sodium oxide | Basic |
(i) Predict whether nitrogen dioxide is acidic or basic. Explain your answer.
▶️Answer/Explanation
Answer:
Nitrogen dioxide is acidic. Explanation:
Nitrogen dioxide is a non-metal oxide, and non-metal oxides are generally acidic. When dissolved in water, nitrogen dioxide forms nitric acid, which is acidic.
(ii) Nitrogen dioxide is an air pollutant. Describe one human activity that releases nitrogen dioxide into the air.
▶️Answer/Explanation
Answer:
Burning of fossil fuels in car engines releases nitrogen dioxide into the air. Explanation:
When fossil fuels are burned in car engines, nitrogen in the air reacts with oxygen at high temperatures to form nitrogen dioxide, which is then released into the atmosphere.
(iii) Identify one other gaseous air pollutant that is harmful to humans.
▶️Answer/Explanation
Answer:
Carbon monoxide (CO) is another gaseous air pollutant that is harmful to humans. Explanation:
Carbon monoxide is a toxic gas that can interfere with the blood’s ability to carry oxygen, leading to health problems such as headaches, dizziness, and even death in high concentrations.
Question
(a) Fig. 3.1 shows a skier at the top of a slope.
(i) A skier travels 310.5 m in 20 s. Calculate the average speed of the skier.
▶️Answer/Explanation
Solution:
Average speed is calculated using the formula:
\[ \text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} \]
Given:
Total distance = 310.5 m
Total time = 20 s
\[ \text{Average speed} = \frac{310.5}{20} = 15.525 \, \text{m/s} \]
Therefore, the average speed of the skier is 15.5 m/s (rounded to one decimal place).
Answer: 15.5 m/s
(ii) Fig. 3.2 shows a speed-time graph of the skier.
Use Fig. 3.2 to determine the distance travelled while the skier has constant acceleration during the first 8 seconds.
▶️Answer/Explanation
Solution:
To find the distance travelled during constant acceleration, we calculate the area under the speed-time graph for the first 8 seconds. The area under the graph represents the distance travelled.
From the graph, the speed increases linearly from 0 m/s to 23 m/s in 8 seconds. The shape under the graph is a triangle, so the area is:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
Here, the base is 8 seconds, and the height is 23 m/s.
\[ \text{Area} = \frac{1}{2} \times 8 \times 23 = 92 \, \text{m} \]
Therefore, the distance travelled during the first 8 seconds is 92 m.
Answer: 92 m
(iii) State the name of the force that impedes the skier’s motion.
▶️Answer/Explanation
Solution:
The force that impedes the skier’s motion is friction. Friction acts opposite to the direction of motion, slowing the skier down.
Answer: Friction
(b)(i) The skier has a mass of 85 kg. The gravitational field strength \( g \) is 10 N/kg. Calculate the weight of the skier.
▶️Answer/Explanation
Solution:
Weight is calculated using the formula:
\[ \text{Weight} = \text{mass} \times \text{gravitational field strength} \]
Given:
Mass = 85 kg
Gravitational field strength \( g = 10 \, \text{N/kg} \)
\[ \text{Weight} = 85 \times 10 = 850 \, \text{N} \]
Therefore, the weight of the skier is 850 N.
Answer: 850 N
(ii) State the source of the gravitational field that causes the skier to accelerate down a slope.
▶️Answer/Explanation
Solution:
The source of the gravitational field that causes the skier to accelerate down a slope is the Earth. The Earth’s gravitational field exerts a force on the skier, causing acceleration.
Answer: The Earth
(iii) When the skier goes to the top of a slope, he does work. As he climbs, his gravitational potential energy increases. Choose from the list the correct word to complete the sentence below:
created gained lost transferred
The work done by the skier is equal to the total energy ________.
▶️Answer/Explanation
Solution:
The correct word to complete the sentence is transferred. The work done by the skier is equal to the total energy transferred to increase his gravitational potential energy.
Answer: transferred
Question
(a) Fig. 3.1 shows a distance-time graph of a girl’s journey to school.
(i) Write the letter X on part of the graph where the girl is walking fastest.
▶️Answer/Explanation
The girl is walking fastest where the gradient of the graph is steepest. This is typically between t = 500s and t = 800s. Therefore, place the letter X on this part of the graph.
(ii) Write the letter Y on part of the graph where the girl is not moving for a period of time.
▶️Answer/Explanation
The girl is not moving where the graph is horizontal. This is typically between t = 300s and t = 500s. Therefore, place the letter Y on this part of the graph.
(iii) The girl walks a total distance of 400 m in 800 s. Calculate her average speed.
▶️Answer/Explanation
Average speed is calculated using the formula:
\[ \text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} = \frac{400 \, \text{m}}{800 \, \text{s}} = 0.5 \, \text{m/s} \]
Therefore, the girl’s average speed is 0.5 m/s.
(b) At school, the girl places a brick onto a board with a rough surface, and raises one end of the board until the brick moves. Fig. 3.2 shows the angle of the board when the brick starts to move.
(i) Name the force that prevents the brick from moving before the board is raised to 40°.
▶️Answer/Explanation
The force that prevents the brick from moving is friction.
(ii) Suggest how the motion of the brick would be different if a board with a smooth surface was used.
▶️Answer/Explanation
If a board with a smooth surface was used, the brick would move faster or start to move at a shallower angle (less than 40°) because there would be less friction acting against the motion.
(iii) State the type of energy that decreases as the brick moves down the board.
▶️Answer/Explanation
As the brick moves down the board, its gravitational potential energy decreases.
(c) The girl then clamps a ruler to the side of a table as shown in Fig. 3.3.
She applies a force of 40.0 N to the end of the ruler which is 0.27 m from the edge of the table. Calculate the moment of the force about the edge of the table.
▶️Answer/Explanation
The moment of a force is calculated using the formula:
\[ \text{Moment} = \text{Force} \times \text{Distance} = 40.0 \, \text{N} \times 0.27 \, \text{m} = 10.8 \, \text{Nm} \]
Therefore, the moment of the force is 10.8 Nm.
Question
(a) A girl runs around a 400 m athletics track. State a device she could use to measure precisely the time this takes.
▶️Answer/Explanation
Answer: stopwatch
Explanation: A stopwatch is a precise device used to measure time intervals, making it suitable for timing the girl’s run around the track.
(b) Fig. 3.1 shows the speed-time graph for her run around the track.
(i) Label with the letter X a point on the graph when the girl is running at constant speed.
▶️Answer/Explanation
Answer: X anywhere on the horizontal section of the graph.
Explanation: A horizontal line on a speed-time graph indicates constant speed, so any point on this section can be labeled as X.
(ii) Label with the letter Y a point on the graph when the girl is at rest.
▶️Answer/Explanation
Answer: Y at t = 0 s or t = 110 s.
Explanation: The girl is at rest when her speed is zero, which occurs at the start (t = 0 s) and the end (t = 110 s) of the run.
(iii) The girl’s deceleration is greater than her acceleration. Describe the evidence for this from the graph.
▶️Answer/Explanation
Answer: The gradient of the graph is steeper during deceleration than during acceleration.
Explanation: A steeper gradient indicates a greater change in speed over a shorter time, meaning the girl decelerates more quickly than she accelerates.
(iv) Calculate the distance travelled by the girl in the first 15 seconds of her run.
▶️Answer/Explanation
Answer: 30 m
Explanation: The distance travelled can be calculated using the area under the speed-time graph. For the first 15 seconds, the graph forms a triangle with a base of 15 s and a height of 4 m/s. The area (distance) is given by:
\[ \text{Distance} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 15 \times 4 = 30 \, \text{m} \]
(c) When she returns home, the girl rings the doorbell. The electric circuit for the doorbell contains a cell, a switch, and an electric bell all connected in series.
is the symbol for an electric bell.
(i) Complete the circuit diagram for the doorbell.
▶️Answer/Explanation
Answer: The circuit diagram should show a cell, a switch, and an electric bell connected in series.
Explanation: In a series circuit, all components are connected end-to-end, so the current flows through each component in turn. The cell provides the energy, the switch controls the flow of current, and the electric bell produces the sound.
(ii) The potential difference across the electric bell is 6 V. The resistance of the electric bell is 2 Ω. Calculate the current in the circuit.
▶️Answer/Explanation
Answer: 3 A
Explanation: Using Ohm’s Law, \( V = IR \), the current \( I \) can be calculated as:
\[ I = \frac{V}{R} = \frac{6}{2} = 3 \, \text{A} \]
(iii) The girl hears the bell clearly. State the approximate range of audible frequencies that the girl is able to hear with healthy hearing.
▶️Answer/Explanation
Answer: 20 Hz to 20,000 Hz
Explanation: The human ear can typically detect sound frequencies in the range of 20 Hz to 20,000 Hz, which is considered the audible range for healthy hearing.
Question
(a) A girl is on a bridge over a river.
(i) Complete the sentences by choosing the correct words or phrases from the list.
Each word or phrase may be used once, more than once or not at all.
chemical constant decreasing friction gravitational potential
increasing joules kinetic newtons weight
The girl picks up a stone and drops it over the side of the bridge.
The stone loses ………………. energy and gains ………………. energy.
The stone falls with ………………. acceleration due to gravity.
The vertical force acting upwards on the stone as it falls is called ………………. and is due to air resistance.
▶️Answer/Explanation
The stone loses gravitational potential energy and gains kinetic energy.
The stone falls with constant acceleration due to gravity.
The vertical force acting upwards on the stone as it falls is called friction and is due to air resistance.
(ii) The river is 30 m below the bridge. After 1.7 s the stone hits the surface of the water. Calculate the average speed of the falling stone.
▶️Answer/Explanation
To calculate the average speed, use the formula:
\[ \text{speed} = \frac{\text{distance}}{\text{time}} \]
Given: distance = 30 m, time = 1.7 s
\[ \text{speed} = \frac{30}{1.7} \approx 17.65 \, \text{m/s} \]
So, the average speed is approximately 17.65 m/s.
(iii) State the source of the gravitational field that is accelerating the stone vertically downwards.
▶️Answer/Explanation
The source of the gravitational field is Earth.
(b) The stone enters the water.
(i) The stone enters the water. Describe how the force of water acting on the stone affects the downwards motion of the stone.
▶️Answer/Explanation
The force of water acting on the stone slows it down or causes it to decelerate.
(ii) The stone enters the water with 450 J of kinetic energy. 200 J is transferred to kinetic energy of the water. 100 J is transferred to thermal energy of the water. 2 J is transferred to sound energy. Determine the remaining kinetic energy of the stone.
▶️Answer/Explanation
To find the remaining kinetic energy, subtract the energy transferred to other forms from the initial kinetic energy:
\[ \text{Remaining kinetic energy} = 450 \, \text{J} – (200 \, \text{J} + 100 \, \text{J} + 2 \, \text{J}) \]
\[ \text{Remaining kinetic energy} = 450 \, \text{J} – 302 \, \text{J} = 148 \, \text{J} \]
So, the remaining kinetic energy is 148 J.
(c) A hydroelectric power station is being built in the river valley.
(i) Describe how electrical energy is obtained from the water behind a hydroelectric dam.
▶️Answer/Explanation
Electrical energy is obtained from the water behind a hydroelectric dam by:
- Water stored behind the dam flows through turbines.
- The flowing water provides kinetic energy to the turbines, causing them to turn.
- The turbines are connected to generators, which convert the kinetic energy into electrical energy.
(ii) The power cables from the power station are supported by pylons. Fig. 3.1 shows the arrangement of the cables between the pylons.
Describe the effect of cold weather on the length of the cables between the pylons.
▶️Answer/Explanation
In cold weather, the cables contract or get shorter due to the decrease in temperature.
(iii) The pylons are spaced equally so that the weight of the cables on each side of the pylon balance. This means the pylons are in equilibrium. State the resultant turning effect on the pylons.
▶️Answer/Explanation
The resultant turning effect on the pylons is zero or none because the forces are balanced.