# Gravitation potential energy question help

by jbjohnybaker
Tags: earth, gravity, mgy, physics, potentital
 P: 19 1. The problem statement, all variables and given/known data A 68.5-kg skier rides a 2.56-km ski lift from the base of a mountain to the top. The lift is at an angle of 13.9° to the horizontal. Determine the skier’s gravitational potential energy at the top of the mountain relative to the base of the mountain. 2. Relevant equations Eg= mg delta y 3. The attempt at a solution eg = (68.5)(9.81)(2560) = 1720281.6 J The answer in the textbook is 4.13x10^5 J :S
 P: 242 hello, you have not accounted for the angle. the ski lift does not go straight up, it goes up a slope.
P: 19
 Quote by eczeno hello, you have not accounted for the angle. the ski lift does not go straight up, it goes up a slope.
I have been taught that "the value of delta y is the vertical displacement of the object. This means that the horizontal path of an object follows in changing its vertical height is not significant" :S

P: 242

## Gravitation potential energy question help

that is correct, but you have the wrong value for delta y. the lift travels a total distance of 2.56 km, but that is not the change in altitude, that is how long the cables are.
P: 19
 Quote by eczeno that is correct, but you have the wrong value for delta y. the lift travels a total distance of 2.56 km, but that is not the change in altitude, that is how long the cables are.
is it right?

eg = (68.5)(sin13.5)(9.81)(2560)
 P: 242 looks good.
 P: 19 thank you very much.
 P: 242 cheers.

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