posted by Anonymous .
A skateboarder with mass ms = 42 kg is standing at the top of a ramp which is hy = 3.7 m above the ground. The skateboarder then jumps on his skateboard and descends down the ramp. His speed at the bottom of the ramp is vf = 6.3 m/s.
Write an expression for the work, Wf, done by the friction force between the ramp and the skateboarder in terms of the variables given in the problem statement.
The ramp makes an angle θ with the ground, where θ = 30 degrees. Write an expression for the magnitude of the friction force, fr, between the ramp and the skateboarder.