A mass M is hauled from ground level up an inclined plane that makes an angle [0] with the horizontal by means of a rope passing over a frictionless pulley. The mass is pulled along until it reaches a height of H.
a)Show that if the contact between the mass and ramp is frictionless, the work done by the tension in the rope (or equivalently, by the person hauling on the rope) is independent of the angle [0].
b)Calculate the work done by the tension in the rope as a function of the ramp angle [0] if the coefficient of kinetic friction between the mass and the surface is U_k.
I have no idea how to do (a). I thought angle is needed to do the calculation.
For (b): I don't know if I did it right or not...
W=Fd
f_k = U_k N
N=mg cos [0]
F=U_k mg cos [0]