How Much Work is Done Pushing a Crate Up a Plank?

[lilmissbossy]

Homework Statement

force F is required to push a crate of mass m up a plank of length L into a truck whose platform is a vertical distance h above the road.

a)How much work is done pusing the crate up the plank m=100kg, L=5m, F=490N h=1.2m
b)what is the increase in PE of the crate once the crate is on the platform

Homework Equations

W=Fxd
PE=mgh

The Attempt at a Solution

ok so my working is

W=Fxd
W=490Nx5m
W=2450N

and

PE=mgh
PE=(100kg)(9.8ms-1)(1.2m)
PE=1176 N

Hmmmmmmm...i think they are right

 

[Defennder]

Yeah it looks ok, provided no friction is involved and F is directed along the length of L.

 

[lilmissbossy]

Excellent i finally got one right by myself!