Question

A ball rolls onto the path of your car as you drive down a quiet neighborhood street. to avoid hitting the child that runs to retrieve the ball, you apply your brakes for 1.20 s. the car slows down from 15.0 m/s to 9.00 m/s. the mass of the car is 1290 kg. (b) how far did the car move while braking?

Answer 1

Since the acceleration of car is uniform so the distance traveled by car while brakes are applied is given by

`d = (v_f + v_i)/(2)*t`

given that

`v_f = 9 m/s`

`v_i = 15 m/s`

`t = 1.20 s`

now plug in all data in above formula

`d = (15 + 9)/(2) * 1.2`

`d = 14.4 m`

so car will cover 14.4 m distance while it apply brakes