It takes you 5 hrs to climb the top of a peak. The altitude of the peak is 400m, and you started from your camp that is an altitude of 300m. Estimate your power output during the climb.

First i found that you move 1000m in 5 hrs, which would be .0556m/sec. I know that to find power you use the equation P= dW/dt..so change in work of change in time..im stuck after that..i don't know how to find the force used

Huh?

Force is gravity: mg

You have to know your weight mg. Use your actual weight, in Newtons.