Question

a 3 kg block slides down a frictionless plane inclined 20 degrees to the horizontal. If the length of the plane's surface is 1.50m, how much work is done, and by what force?


suppose the coefficient of kinetic friction between the block and the plane. What would be the net work done in this case?

Answer 1

sorry i forgot to add the coefficient of friction is .275

Answer 2

Gravity does the work which is equal to the change in potential energy, m g h
here h = 1.50 sin 20
so
m g h = 3*9.8 *1.5*sin 20

friction will do negative work
mu m g cos 20 * 1.50

subtract that from m g h to get net

Answer 3

So mu = .275