CIE iGCSE Co-Ordinated Science P1.3 Mass and weight Exam Style Questions Paper 3
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) Fig. 6.1 shows an elephant pushing a log up a hill.
(i) State the two quantities that need to be measured to calculate the work done by the elephant on the log.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
(ii) State the form of energy gained by the elephant as it moves up the hill at constant speed.
…………………………………………………………………………………………………………………….
(b) The elephant has a mass of 3500kg and the log has a mass of 180kg.
(i) Calculate the combined weight of the elephant and the tree trunk.
The gravitational field strength, g, is 10N/kg.
weight = ……………………………………………… N
(ii) The volume of the elephant is 3.4m$^{3}$.
Calculate the average density of the elephant.
density = ………………………………………. kg/m$^{3}$
(c) A scientist takes some measurements of the elephant.
Table 6.1 shows the measurements taken.
Complete Table 6.1 with suitable units for these measurements.
One has been done for you.
▶️Answer/Explanation
Ans: 6(a)(i) force ;
distance ;
6(a)(ii) gravitational potential energy ;
6(b)(i) W = mg (symbols or words) or (3500 + 180) × 10 ;
= 36 800 (N) ;
6(b)(ii) density = mass ÷ volume (symbols or words) or 3500 ÷ 3.4 ;
1029 (kg / m$^{3}$ ) ;
6(c)
Question
Fig. 9.1 shows an aircraft at rest on a runway.
(a) The mass of the aircraft is 400 000 kg.
Calculate the weight of the aircraft. The gravitational field strength, \( g \), is 10 N/kg. (Topic – P1.3)
▶️Answer/Explanation
Weight = 4,000,000 N
Explanation: Weight is calculated using the formula \( W = m \times g \), where \( m \) is mass and \( g \) is gravitational field strength. Substituting the values, \( W = 400,000 \, \text{kg} \times 10 \, \text{N/kg} = 4,000,000 \, \text{N} \).
(b) The aircraft starts from rest and accelerates along the straight runway. The aircraft engines produce a constant horizontal thrust force of 1,200,000 N. A constant frictional force of 500,000 N acts on the aircraft. (Topic – P1.5)
(i) Calculate the resultant horizontal force acting on the aircraft.
▶️Answer/Explanation
Resultant force = 700,000 N
Explanation: The resultant force is calculated by subtracting the frictional force from the thrust force: \( F_{\text{resultant}} = 1,200,000 \, \text{N} – 500,000 \, \text{N} = 700,000 \, \text{N} \).
(ii) Explain why the aircraft accelerates.
▶️Answer/Explanation
The aircraft accelerates because there is a resultant force acting on it.
Explanation: According to Newton’s Second Law of Motion, an object accelerates when there is a resultant force acting on it. In this case, the resultant force of 700,000 N causes the aircraft to accelerate.
(c) Fig. 9.2 shows a TV monitor in the cabin of the aircraft and the energy transferred each second by the monitor.
(i) The number of joules of sound energy transferred per second is shown as XJ. Calculate the value of X. (Topic – P1.6)
▶️Answer/Explanation
X = 1 J
Explanation: The total energy input is 200 J, and the energy outputs are 119 J (light) and 80 J (thermal). Therefore, the sound energy \( X = 200 \, \text{J} – (119 \, \text{J} + 80 \, \text{J}) = 1 \, \text{J} \).
(ii) The monitor has a resistance of 1900 Ω. The current passing through the monitor when in use is 0.060 A.
Calculate the potential difference across the monitor. State the unit of your answer. (Topic – P4.2)
▶️Answer/Explanation
Potential difference = 114 V
Explanation: The potential difference (V) is calculated using Ohm’s Law: \( V = I \times R \). Substituting the values, \( V = 0.060 \, \text{A} \times 1900 \, \Omega = 114 \, \text{V} \).
(iii) The current of 0.060 A is the same as 60 mA. The fuse in the electrical supply to the monitor has to be replaced. Several fuse ratings are available.
10 mA 50 mA 100 mA 250 mA
State which fuse is the correct choice. Explain your answer. (Topic – P4.4)
▶️Answer/Explanation
Fuse = 100 mA
Explanation: The fuse rating should be higher than the maximum current (60 mA) but not too much higher to ensure safety. A 100 mA fuse is the most appropriate choice as it is the smallest value above 60 mA.
Question
(a) A person standing on a warm, sunny beach is exposed to several forms of electromagnetic radiation.
Fig. 12.1 shows part of the electromagnetic spectrum.
Complete Fig. 12.1 by writing the names of the other two forms of electromagnetic radiation in the correct places.
(b) The person stands with both feet on some very soft sand on the beach.
When one foot is lifted off the sand, the other foot sinks deeper into the sand.
Explain why this happens.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
(c) A sample of sand has a mass of 8000kg.
This sand has a density of 1600kg/m$^{3}$.
(i) Calculate the volume of this sample of sand.
volume = …………………………………. m$^{3}$
(ii) Show that the weight of this sample of sand is 80000N.
The gravitational field strength, g, is 10N/kg.
(d) A piece of glass has been left on the beach. The glass acts like a convex lens focusing the Sun’s rays.
Fig. 12.2 shows two rays of light 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.
(ii) State the name of point F.
…………………………………………………………………………………………………………………….
(iii) On Fig. 12.2, draw a double headed arrow (↔) to indicate the focal length of the lens.
▶️Answer/Explanation
Ans: 12(a)
microwaves in correct place ;
X-rays in correct place ;
12(b) area decreases ;
so pressure increases ;
12(c)(i) volume = mass / density (in any form symbols or words) or 8000 / 1600 ;
= 5 (m$^{3}$ ) ;
12(c)(ii) 8000 × 10 ;
(= 80 000 N)
12(d)(i) rays meet at focus (F) ;