OCR 2023 GCE Physics A H156/02: Depth in physics AS Level Question Paper & Mark Scheme (Merged)

The brakes of a car of mass 1200 kg are being tested on a track. The driver sees a hazard and applies the brakes. The graph shows the variation of the velocity v of the car with time t from when the driver sees the hazard to when the car stops. 20 v /m s –1 15 10 5 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 t/ s (a) (i) Calculate the acceleration a of the car while the brakes are applied. a = ................................................. m s –2 [1] (ii) Calculate the average braking force F while the brakes are applied. F = .......................................................N [1] 13 © OCR 2023 Turn over (iii) Calculate the total stopping distance d of the car. d = ...................................................... m [2] (iv) Calculate the work W done by the brakes to stop the car. W = ....................................................... J [2] (b) The same driver in the same car repeats the test at half the initial velocity. The braking force is constant. On the graph, draw the variation of velocity of the car from the time the driver sees the hazard to the time the car stops. [2] (c) Explain how your graph in (b) would change if: (i) the driver was tired ................................................................................................................................................... .............................................................................................................................................. [1] (ii) the surface of the track was more resistiv