Rock Climbing: Work Done by Gravity & Change in GPE

[jabbie3]

Homework Statement

A rock climber of mass 92.1 kg starts at the base of a cliff and climbs to the top (h = 33.8 m). He then walks along the plateau at the top for a distance of L = 289.9 m.

(a) Find the work done by gravity.
(b) What is the change in the gravitational potential energy of the rock climber.

Homework Equations

Im still learning this stuff and am clueless thus far.

The Attempt at a Solution

This is why i need help..

THANKS!

 

[Nabeshin]

This problem is very similar to the others you have posted so far. Look at the solutions to those and you should be able to figure out this one.

 

[jabbie3]

I'm trying. I understand PE=mgy but it just isn't working for me.

 

[Nabeshin]

Consider the fact that that work can have a positive or negative sign, depending on if the force is working in the same or opposite direction of motion.