Question

Say a block starts at rest at the top of a ramp (at 25 degrees). If the coefficient of kinetic friction between the block and the ramp is 0.7, how far would the block slide along the ramp before coming to a stop? Also say the block's vertical position at the top of the ramp is 0.5 m.

Answer 1

Forces acting on the block are ,

i) along the plane and downwards

ii) perpendicular to plane and towards it.

iii) Normal force perpendicular to plane and away from it.

iv) Force of friction along the plane and upwards.

Net force perpendicular to plane is zero , hence  

Static frictional force

Since the body starts from rest, the body will move only if the downward gravitational force exceeds the maximum frictional force.

and coefficient of friction is

so

Hence the block stays at rest . It does not move.

Distance moved by block is zero.