A stewardess pulls her 70 N flight bag a distance of 200 m along an airport floor at constant speed. The force she exerts is 40 N at an angle of 50 degrees above the horizontal. Find (a) the work she does, (b) the work done by the force of friction, and (c) the coefficient of kinetic friction between her flight bag and the floor.

I only know how to do (a). How would I do (b) and (c).

(a) (5kg)(9.8m/s^2)(sin30)(200m)=5140J