 #1
greg_rack
Gold Member
 295
 68
 Homework Statement:

A block of weight ##150N## is pulled up, by a force, on an inclined plane, reaching a height of ##2m##.
The force makes a total work of ##400J##. The block starts and ends its path at zero velocity.
How much work has the friction force made, during the lift of the block?
 Relevant Equations:
 none
I'm aware of the triviality of this problem, but I'm quite confused on how to solve it.
I thought that, for the conservation on energy, if the block starts from zero velocity its energy at the end of the path must also be zero: ##mghL_{tot}+L_{friction}=0##... but that is all but convincing me.
I thought that, for the conservation on energy, if the block starts from zero velocity its energy at the end of the path must also be zero: ##mghL_{tot}+L_{friction}=0##... but that is all but convincing me.