Question

A motorcyclist sees a branch in the road and slow down at -6.42 m/s^2. If it takes them 2.85s to stop, what was their starting velocity?

Answer 1

18.297 m/s

Step-by-step explanation:

You use the formula vf=vi+at.

Because the motorcyclist is stopping, the final velocity would be 0 m/s.

We know that the time is 2.85s and the acceleration is -6.42m/s^2.

Plug these numbers into the formula to get 0=vi+(-6.42m/s^2)(2.85s)

Simplify it to -vi=(-6.42m/s^2)(2.85s)

When you multiply the time and the acceleration together, you get

-18.297 m/s.

You plug that into the equation to get -vi=-18.297 m/s.

Divide both by -1 and you'll get 18.297 m/s as the answer.