- #1

Priscilla

- 31

- 0

## Homework Statement

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. The building of the Egyptian pyramids and many other ancient construction jobs used such ramps. Logs were sometimes used as rollers to reduce friction.

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 if the coefficient of kinetic friction between the mass and the surface is U_k.

## Homework Equations

W=Fd

f_k = U_k*N

( N = normal force f_k = kinetic friction)

## The Attempt at a Solution

6a, I have no idea how to prove it. Because I thought the tension is dependent of the angle. The angle is used to calculate the F_N, Fs...

6b

W=Fd d = H

N=mg cos

*0*

F=U_k mg cos

*0*

W=U_k mg cos

*0*H