Coefficient of Kinetic Friction on an Inclined Plane

Moderate

You have a brick and inclined plane.

Which of the following would be an effective method to determine the coefficient of kinetic friction between the brick and the plane?

A

Put the brick on the plane at an angle so that it accelerates downward. Pull the brick up the plane with a spring scale until the block is moving slowly at a constant speed down the plane. Divide the pull on the scale by the product of the weight and cosine of the angle to calculate the coefficient of kinetic friction.

B

Put the brick on the plane at a low angle so that it does not move. Pull the brick up the plane with a force sensor until the block just begins to slide upward at a slow constant speed. Divide the pull on the scale by the normal force to calculate the coefficient of kinetic friction.

C

Put the brick on the plane at an angle so that it moves downward at a constant speed. Divide the weight of the block by the tangent of the angle to calculate the coefficient of kinetic friction.

D

Put the brick on the plane at a high angle so that it accelerates down the plane. Lower the top of the plane to decrease the angle until the block just begins to slide at a slow constant speed but does not stop. Back it off if necessary. The tangent of the angle is the coefficient of kinetic friction.