What is the coefficient of kinetic friction?

A block of mass m1 sits on a track tilted at an angle θ. A second mass hangs freely from a string, which runs over a pulley and attaches to the first mass. You add many paperclips to the hanging mass, making its total mass m2, so that it accelerates downwards and drags the block up the ramp.

Make a free-body diagram for each block. Make a table showing all the forces on each block in the x- and y-directions.

Hint: the axes for one block will be tilted, the axes for the other block will not

Write down equations for total forces in X-direction, and total forces in Y-direction. This time, the net forces may NOT add up to zero.

You measure the time it takes for the block to slide d = 80.0 cm up the ramp. It takes t = 1.57 s.

What is the coefficient of kinetic friction μ_k?