Speed and distance question

Question

A rocket is launched straight up with a constant acceleration of 18 m/s2 . After 150 seconds, (a) how fast is the rocket moving and (b) how far has it travelled?

I think it's moving 2,700 m/s but I'm not too sure

Answer 1

You have to adjust for acceleration downwards due to gravity.

Net acceleration upwards = 18 - 9.81 = 8.19 m/s/s

So after 150 s, 150 x 8.19 = 1228.5 m/s

Distance s = ut + 0.5 at²

u = 0

t = 150

a = 8.19

you can calculate s