# Gravitational Potential energy on an incline

1. Apr 25, 2012

Hello all, I'm new to the forum here and desperately need some help in some basic physics concepts that I need to have a firm grasp on for the MCAT.

My question is about PE on an inclined plane. For example, there are 3 possible scenarios (the height and mass remains the same for each scenario). Scenario 1 has a ramp angled at 30, scenario 2 has a ramp angled at 60, and the last scenario has no ramp at all- the person must lift it from the ground to the desired height.

What I am asking is that when PE (or U)= mgh, does g remain the same at 9.8m/s^2 or is it affected by the angle of the ramp, ie gsin30? And could you please explain why?

I know when you solve for acceleration in an unrelated problem to PE you do, but I'm not sure about for just when solving for PE.

Thanks!

2. Apr 27, 2012

### elegysix

potential energy only depends on the height, mgh. whatever the difference in height at the start and end, mg(h2-h1) will be the change in potential energy, either becoming kinetic (rolling down) or becoming potential (going up ramp). the potential has nothing to do with the ramp, only the change in height. g never changes