# physics

posted by .

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.

## Similar Questions

1. ### physics

Find the acceleration down the ramp: skateboarder starts from rest at the top of a 12.5 m slick ramp that makes a 25 degree angle with the horizontal. (coefficient of rolling friction is negligible). Combined mass of skateboarder and …
2. ### physics

A skateboarder shoots off a ramp with a velocity of 7.9 m/s, directed at an angle of 56° above the horizontal. The end of the ramp is 1.3 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically …
3. ### physics

A skateboarder shoots off a ramp with a velocity of 6.8 m/s, directed at an angle of 54° above the horizontal. The end of the ramp is 1.3 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically …
4. ### Physics

A skateboarder shoots off a ramp with a velocity of 6.5 m/s, directed at an angle of 62° above the horizontal. The end of the ramp is 1.5 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically …
5. ### Physics

A skateboarder shoots off a ramp with a velocity of 6.5 m/s, directed at an angle of 62° above the horizontal. The end of the ramp is 1.5 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically …
6. ### physics mechanical energy

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. …
7. ### Physics

A skateboarder shoots off a ramp with a velocity of 5.7 m/s, directed at an angle of 58° above the horizontal. The end of the ramp is 1.3 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically …
8. ### physics30

After performing a trick above the rim of a skateboard ramp, a 56 kg skateboarder lands on the ramp 3.5 m above ground level with a downward velocity of 4.0 m/s. Ep = 0.0 J Ground level. Friction in the wheels of the skateboard and …
9. ### physics

A skateboarder starts up a 1.30m high, 25.0° ramp at a speed of 6.70m/s. The skateboard wheels roll without friction. How far from the end of the ramp does the skateboarder touch down?
10. ### Physics

A skateboarder starts up a 1.0-m-high, 30∘ ramp at a speed of 7.2 m/s . The skateboard wheels roll without friction. At the top, she leaves the ramp and sails through the air. How far from the end of the ramp does the skateboarder …

More Similar Questions