Magnitude of the average force of air resistance on a rocket

[IAmPat]

Homework Statement

An engine supplies an upward force of 9.00N to an initially stationary toy rocket, of mass 54.0g, for a distance of 25.0m. The rocket rises to a height of 339 meters before falling back to the ground. What was the magnitude of the average force of air resistance on the rocket during the upward trip?

2. The attempt at a solution

Fa = Applied Force = 9N

Work done by Engine: F * Change in Y = 9 N * 25m = 225J

PEf = Final Potential Energy
PEf = mgh = (.0054)(9.8)(339)
PEf = 17.94 J

-PEf is also the work done by gravity

I'm actually really confused as to how to go about this problem. Never had to do one like this really. If someone could give me a starting point, I'll try to work out more from there.

 

[PhanthomJay]

First correct the mass of the rocket to read 0.054 kg. With that change, your calcs for the work done by the engine and gravity are correct.

Now what about the work done by the air and the initial and final kinetic energies?. Enter that into the Work-Energy equation, you know, the one that says the total work done by all forces acting on the object is equal to the change in the kinetic energy of the object?