CIE iGCSE Co-Ordinated Science P1.6.2 Work Exam Style Questions Paper 4
Question
A car is moving at 9.0m/s along a flat horizontal road.
The driver applies the brakes, and the car slows down and stops.
(a) Fig. 12.1 shows a speed–time graph for the car as it brakes.
(i) Complete the sentence to describe one energy transfer that takes place.
The kinetic energy of the car is transferred to …………………………………. energy of the surroundings.
(ii) The braking force acting on the car is 2500N.
Calculate the work done by the braking force in stopping the car.
work done = ……………………………………………… J
(b) Fig. 12.2 shows the driver pushing the brake pedal with his foot.
The driver applies a force of 35N on the brake pedal.
The force is applied 0.22m from the pivot.
Calculate the moment of the force about the pivot.
moment = ………………………………………….. Nm
(c) When the brakes are applied, a lamp switches on to alert other drivers.
(i) The lamp uses a current of 3.0A and has a power output of 36W.
Calculate the potential difference across the lamp.
potential difference = ……………………………………………… V
(ii) The lamp emits light with a wavelength of 7.5 × 10$^{-1}$m.
Calculate the frequency of the light emitted by the lamp.
State the unit for your answer.
frequency = ………………………. unit …………………
▶️Answer/Explanation
Ans : 12(a)(i) thermal ;
12(a)(ii) (area under the graph to determine distance) 0.5 × 9.0 × 6.0 or 27 (m) ;
evidence of W = Fd or 2500 × 27 ;
68 000 (J) ;
12(b) evidence of moment = Fd or 35 × 0.22 ;
7.7 (N m) ;
12(c)(i) evidence of V = P ÷ I or 36 ÷ 3.(0) ;
12 (V) ;
12(c)(ii) use of 3 × 10$^{-1}$ (m/ s) ;
evidence of f = v ÷ λ or 3 × 10$^{8}$ ÷ 7.5× 10$^{-7}$ ;
4.0 × 10$^{14}$ ;
Hz ;