Physics Kinematics in One Dimension

[aeubz]

Wow... I'm fried from doing this problem... Any help would be nice...

A 1000kg weather rocket is launched straight up. The rocket motor provides a constant acceleration for 16s, then the motor stops. The rocket altitude 20s after launch is 5100m. You can ignore any effects of air resistance.
a) What was the rocket's acceleration during the first 16s?
b) What is the rocket's speed as it passes through a cloud 5100m above the ground.

My work is scanned... (#7 circled)

Personally, I think not enough info is given..

 

[catkin]

There is enough info.

What have you tried so far?

Have you got an expression for the speed of the rocket after 16 seconds?