# Thread: acceleration of car is required to be calculated

1. ## acceleration of car is required to be calculated

If a car required 18 seconds to stop to zero speed while it was moving at 50 Km/h, how can we calculate the acceleration or deceleration of car during crash

2. ## Re: acceleration of car is required to be calculated

Originally Posted by moonnightingale
If a car required 18 seconds to stop to zero speed while it was moving at 50 Km/h, how can we calculate the acceleration or deceleration of car during crash
$a = \dfrac{v-u}{t}$

You know v, u and t. It is perfectly acceptable for a to be negative.

3. ## Re: acceleration of car is required to be calculated

the answer coes to be -0.77 m/sec
is it correct

4. ## Re: acceleration of car is required to be calculated

Originally Posted by moonnightingale
the answer coes to be -0.77 m/sec
is it correct
Remember that acceleration is measured in $\text{m}\cdot \text{s}^{-2}$