The Student Room Group

pulley dynamics question

A stationary 100kg mass is on a slope. The slope is 37 degrees above the horizontal. A weightless, inelastic rope attached to the 100kg mass, passes over a pulley at the top pf the slope and is connected to a vertically hanging 50kg mass. The pulley is weightless and frictionless. The coefficient of friction between the slope and the 100kg mass is 0.3.

My question is, what direction is the 100kg mass moving in, up or down the slope.
Original post by Engineeringbeast

My question is, what direction is the 100kg mass moving in, up or down the slope.


This is a slightly more general answer, as you're told the 100kg mass is stationary.

If the friction wasn't there could you work out which direction the masses would move?

Friction is working in the opposite direction. Is the frictional force required to keep the masses stationary less than the max frictional force? If so, the masses don't move. If not, they'd go in the direction you previously worked out.
(edited 9 years ago)

Quick Reply