How can I calculate the force of friction on a rocket launched at school?

[xCanx]

I have to find the force of friction against a rocket that we launched at school. How would I do that?

I know coefficient = Friction/Fn

I only have Fn, how do I find the frinction?

I'm really lost :(

 

[xCanx]

I have Fg = 0.75 N, so that would be the work done against gravity, right?

So how would I use that to find the force of friction (air resistance in this case, since the rocket is thrust upward)