A driver of a car moving with speed 90km/h saw a child on the road 25m ahead of him .he jammed on the brake and bought the car to rest and retradation of the car

Complete question :

A driver of a car moving with speed 90km/h saw a child on the road 25m ahead of him .he jammed on the brake and bought the car to rest. Calculate the time taken to bring the car to rest and retradation of the car.

t = 2 seconds ; retradation = - 12.5 m/s²

Explanation:

Given that :

Final velocity v = 0

Initial Velocity u = 90 km /hr = (90 * 1000)m / 3600s = 90000m/3600s = 25m/s

Distance = 25 m

Using the relation :

v² = u² + 2aS

where, S = distance covered a = retradation

0 = 25² + 2a(25)

0 = 625 + 50a

50a = - 625

a = - 12.5 m/s²

Time taken (t) :

Using :

v = u + at

0 = 25 + (-12.5 * t)

0 = 25 - 12.5t

12.5t = 25

t = 25 / 12.5

t = 2 seconds

the social contract theory

uncle sam would be tossing and turning in his grave : *)