How to Calculate Work Done by an Escalator?

[sylavel]

Homework Statement

http://img252.imageshack.us/my.php?image=heyheygw0.jpg
Mass=57.1 Kg
Distance 69.5 m
G= 9.8
Theta= 34.9
So I'm trying to find the amount of work done on mass.

Homework Equations

F=ma
Work=Fcos(theta)D

The Attempt at a Solution

Okay so i started out finding Force by Newtons 2nd law.
F=ma
f=57.1(9.8)
F=559.58
Okay so then I went with force to the work fomula.
Work=559.58cos(34.9)69.5
and that gave me 31896.37
but this answer proved to be incorrect?

 

[Astronuc]

Why cos(theta)? Over what height is mass (or weight) lifted?

 

[sylavel]

good question.
sin would prehaps be more fitting =)

 

[ilovemynny]

I have a similar problem like this so if I was to solve this problem would it go like this:
Work=Fsin(theta)D

?