Finding maximum speed..

[aivy]

Hello, I would like some help getting started on this question please:

A rocket accelerates from rest at the rate of 55m/s² for 20.0s. It then moves at a constant speed for 5.0s after which it accelerates at -35m/s² until it stops. What is the maximum speed of the rocket?

 

[skeeter]

some common sense physics ...

max speed = (55 m/s²)(20 s),

after the first 20 seconds it goes no faster, does it?

 

[aivy]

thank you