Question

A car can be brought to rest from a speed of 200 m/s in a time of 2 seconds.Calculate the deceleration

Answer 1

By definition, the acceleration (negative deceleration) is given as follows:

$$a = \dfrac{v_f-v_i}{t}$$

where $v_f = 0m/s$ is the final speed of the car, $v_i = 200m/s$ is its initial speed, $t = 2s$ is the time passed. Thus, obtain:

$$a = \dfrac{0-200m/s}{2s} = -1m/s^2$$

Negative acceleration is called deceleration. Thus, the deceleration is $1m/s^2$.

Answer. $1m/s^2$.