A car is travelling at 25 m/s along a straight road
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A car is travelling at 25 m/s along a straight road. It is brought to rest with uniform deceleration in 5 s, remains stationary for the next 3 s at a traffic light, and then accelerates uniformly to 15 m/s in 4 s as the light turns green.
(a) Draw the velocity–time graph for the entire motion described.
(b) Calculate the magnitude of the deceleration while the car is coming to rest and the magnitude of the acceleration as it moves away from the traffic light.
(c) Determine the total displacement of the car from the moment the brakes are first applied until it reaches 15 m/s again.
(d) Compute the average speed of the car for the whole 12 s interval.