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hyuen9195
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Homework Statement
A 11.0 kg crate is pulled up a rough incline with an initial speed of 1.3 m/s. The pulling
force is 121.0 N parallel to the incline, which makes an angle of 12.6◦ with the horizontal.
The coefficient of kinetic friction is 0.31 and the crate is pulled a distance of 8.0 m.
The acceleration of gravity is 9.81 m/s^2 .
Homework Equations
a) Find the work done by Earth’s gravity
on the crate. Answer in units of J.
The Attempt at a Solution
Fnormal=m*g*costheta
Fnormal=105.3111778N
Fnormal* coefficient of friction=Ffriction
Ffriction=32.64646511N
Fapplied-Ffriction=Fnet
Fnet=88.35353489N
Work=N*m
Work=706.8282791N*m
-(Work*sin12.6)=W done by gravity
Work done by gravity is 154.1898119N*m
I think I did it right, but the computer marked me wrong. Can anyone explained this?