Acar starting from rest accelerates at a rate of 12 m/s2. what is its final speed at the end of 4.0 seconds?

48m/s

Explanation:

First, you have to identify the information the problem is giving you. A car starting from rest means that the initial speed is 0m/s. You also know the acceleration which is 12m/s² and the time which is 4s.

You can use the following formula to calculate the final speed:

Vf = Vo + at

The known values are:

Vo = 0m/s

a =  12m/s²

t = 4s

And now you substitute in the formula

Vf = 0m/s + (12m/s²)(4s)

Vf = 48m/s

So the final speed is 48m/s