Question

A car starts from rest and after 7 seconds it is moving at 42 m/s. What is the car's average acceleration?

Answer 1

`a_{avg}=6ms^-2`

Explanation:

We'll use a simple kinematic equation to solve this.
`v=v_o+at`

Here, given that `v=42ms^-1`, `s=7s` and that it started from rest so `v_o=0ms^-1`, we get
`42=0+a*7=cancel{42}^6/cancel{7}^1=a`

So, that's how we got acceleration.