Posted by eugene on .
A 1kg rocket is fired straight up from level ground. The engine is able to provide a constant 15N of thrust for exactly 5 seconds after which it shuts of completely. Find the maximum height that the rocket achieves.

physics 
bobpursley,
WEll, the impulse given is 15*5 Ns=75Ns
Velocity at burnout= 75Ns/1= 75m/s
What was its altditude at this point?
Vf^2=Vi^2+2ad
where a= (F/m g)
solve for d (height hi)
Now, final height
Vf^2=0=75^22g(hfhi)
solve for hf. 
physics 
Anonymous,
thanks so much...i got 33.3m/s...would u say that's correct?

physics 
charlie,
sorry that was 188 that i got