CIE iGCSE Co-Ordinated Science P1.5.2 Turning effect of forces Exam Style Questions Paper 3
Question
(a) During a journey, a car becomes positively charged with static electricity. State the name of the charged particles that have been removed from the car.
(b) The car has two headlamps powered by the car battery. The lamps are connected in parallel. Complete the circuit diagram in Fig. 12.1 to show two lamps connected in parallel both controlled by one switch. The battery has been drawn for you.
(c) The driver of the car changes a wheel. Fig. 12.2 shows a wheel nut being loosened by a spanner.
The driver uses a force of 1200 N on the spanner. Calculate the moment of this force on the wheel nut in Nm.
(d) The car driver uses a mirror to see behind the car. Fig. 12.3 shows the driver looking into a plane mirror. He can see the reflection of a street lamp.
(i) State the name of the line labelled XY.
(ii) On Fig. 12.3, label the angle of incidence with the letter \(i\).
(iii) Circle two words or phrases that correctly describe the image of the street lamp seen in the mirror.
larger laterally inverted same size smaller upside down
▶️Answer/Explanation
(a) Answer: electrons
Explanation: When a car becomes positively charged, it means that electrons have been removed from it. Electrons are negatively charged particles, so their removal leaves the car with a net positive charge.
(b) Answer: The circuit diagram should show the two lamps connected in parallel with the battery and controlled by one switch. The switch should be placed in the main line before the lamps branch out.
Explanation: In a parallel circuit, each component is connected across the same voltage, and the current divides between the branches. The switch controls both lamps simultaneously.
(c) Answer: 660 Nm
Explanation: The moment of a force is calculated using the formula: \[ \text{Moment} = \text{Force} \times \text{Distance} \] Given that the force is 1200 N and the distance (length of the spanner) is 55 cm (0.55 m), the moment is: \[ \text{Moment} = 1200 \, \text{N} \times 0.55 \, \text{m} = 660 \, \text{Nm} \]
(d)(i) Answer: normal
Explanation: The line labelled XY is the normal, which is an imaginary line perpendicular to the surface of the mirror at the point where the light ray strikes it.
(d)(ii) Answer: The angle of incidence should be labelled with the letter \(i\) between the incident ray and the normal.
Explanation: The angle of incidence is the angle between the incident ray and the normal to the mirror’s surface.
(d)(iii) Answer: same size, laterally inverted
Explanation: The image formed by a plane mirror is always the same size as the object and is laterally inverted (left and right are swapped).
Question
(a) Fig. 3.1 shows a worker changing a lamp on a lamp post.
(i) The worker is lifted up to the top of the lamp post.
State the type of energy that has been gained by the worker when he has reached the top of the lamp post.
▶️Answer/Explanation
Gravitational potential energy.
(ii) As the worker changes the lamp, he drops his screwdriver.
State the type of energy that is gained by the screwdriver as it is falling to the ground.
▶️Answer/Explanation
Kinetic energy.
(iii) The worker applies a horizontal force of 10 N to the top of the lamp post.
The total height of the post is 10 m.
Calculate the moment of the force at the base of the post and state its units.
▶️Answer/Explanation
Moment = Force × Distance = 10 N × 10 m = 100 Nm.
Units: Nm (Newton meters).
(b) The worker switches on the lamp. The lamp emits visible light.
(i) Fig. 3.2 shows an incomplete electromagnetic spectrum.
On Fig. 3.2 write visible light in its correct position.
▶️Answer/Explanation
Visible light should be placed between ultraviolet and infrared on the electromagnetic spectrum.
(ii) Draw a line from each type of electromagnetic radiation to its use. One of the lines has been drawn for you.
▶️Answer/Explanation
Infrared → Heat sensing camera
Microwaves → Television signal transmission
Radio waves → Telephone transmission
X-rays → Airport security bag checking
(iii) Four types of electromagnetic radiation are listed in (b)(ii).
State which of these has the lowest frequency.
▶️Answer/Explanation
Radio waves.
(c) The worker drives a van for 15 minutes and travels 8 km.
Calculate the average speed of the van in m/s.
▶️Answer/Explanation
First, convert 15 minutes to seconds: 15 minutes × 60 seconds/minute = 900 seconds.
Convert 8 km to meters: 8 km × 1000 m/km = 8000 meters.
Average speed = Distance / Time = 8000 m / 900 s ≈ 8.89 m/s.