Thrust of a Rocket: Calculating Force

[Darkmirror]

Homework Statement

[PLAIN]http://img714.imageshack.us/img714/8184/rocketj.png

I am not sure if the problem has enough information to find. However, i tried some of the works.
g=10m/s2( i use gravity as 10 .)

Homework Equations

No idea...

The Attempt at a Solution

I am thinking this formula F = ma to find the thrust.

so my first plan is to find the a(in xy direction) and then get the Force. (not sure if this is a right attempt)
So,

t=(2(275)/10) = 7.4 sec

V(in y dir) = (2(275)(10))^.5 = 74m/s
V(in xy dir) = 74/sin(85) = 74m/s

a(in xy dir)= 74/(7.4*2) =5.3m/s2 (I am pretty sure this part is wrong)

F = ma
F= (26/1000)kg * 5.3 m/s2 = 0.1219 N ( Doesn't make sense lol )

I am new to Physics. So, yea, i am still confusing with some stuffs. Thanks in advanced for helping me.

 

[Spinnor]

How long does the thrust last?

 

[Darkmirror]

How long does the thrust last?

I am srry. I don't have the information..
P.S i just learned Newton's Laws. So ye, i don't know much of physics yet...