1) A 100kg mass is on a ramp that is inclined at 20 degrees to the horizontal. A student pushes up along the ramp with 200N force. This is not sufficient to stop the mass from sliding down the ramp. What is the magnitude of the acceleration down the ramp. HINT. MAKE SURE YOU SET UP AN AXIS ALONG THE RAMP.
Correct Answer: No answer given yet a b c d e
2)Now add friction to the situation above. The mass still slides down the ramp, but with a reduced acceleration because of friction. The coefficient of kinetic friction is 0.10 . What is the new acceleration? The 200N force is still there also. Two hints. Remember frictional force acts in a direction to oppose the motion that would occur if there were no friction. DIRECTION Also the magnitude of friction is equal to the coefficient of friction times the magnitude of the normal force.
3) On the same ramp you can glue down some sand paper of any selected grit. So you can change the coefficient of kinetic friction. What should the coefficient be made in order to make the object slide down at a constant speed? (Constant speed means no acceleration...so also........)