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helppleaseee
Feb23-07, 09:09 PM
A system of pulleys is used to lift an elevator that weighs 3900 newtons. The pulley system uses 9 ropes to support the load. How far would 10700 joules of input work lift the elevator? Assume the pulley system is frictionless.

2. Relevant equations
w=fd
f=ma
w=mg

3. The attempt at a solution
w=fd
10700=fd
and so i tried to solve for f using f=ma...i found m using w=mg (3900=m*9.81=397.55) but we're not given the acceleration so i'm stuck!

MarkusNaslund19
Feb24-07, 02:16 AM
You have the weight of the elevator. So f=3900N? Try that.

helppleaseee
Feb24-07, 04:00 PM
then what do i do with the 9 because there are 9 ropes?
...maybe multiply it??

helppleaseee
Feb24-07, 04:44 PM
nvm i got it...you just ignore the 9 ropes