A car is travelling at when the driver observes an obstacle ahead

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A car is travelling at

72\,\text{km\,h}^{-1}

when the driver observes an obstacle ahead. He takes

0.8\,\text{s}

to react before pressing the brakes. Once applied, the brakes produce a uniform retardation of

5\,\text{m\,s}^{-2}

. What is the total distance the car covers before coming to rest after noticing the obstacle? (a)

48\,\text{m}

(b)

64\,\text{m}

(c)

56\,\text{m}

(d)

40\,\text{m}