Question

A car is traveling at 20 meters/second and is brought to rest by applying brakes over a period of 4 seconds what is its average acceleration over this time interval?

Answer 1

Avg. acceleration = -5 m/s^2.

Answer 2

Answer:

Acceleration of the car is $-5\ m/s^2$

Explanation:

It is given that,

Initial speed of the car, u = 20 m/s

Finally, it brought to rest, v = 0

Time taken, t = 4 s

We need to find the average acceleration over this time interval. The acceleration of an object is given by following formula as :

$a=\dfrac{v-u}{t}$

$a=\dfrac{-(20\ m/s)}{4\ s}$          

$a=-5\ m/s^2$

So, the car is decelerating at $5\ m/s^2$. Hence, this is the required solution.