Question

2. A girl and her bicycle have a total mass of 40 kg. At the top of the hill her speed is 5.0 m/s.

The hill is 10 m high and 100 m long.
If the magnitude of the force of friction as she rides down the hill is 20 N, what is her speed
at the bottom of the hill? (Take g=9.8 m/s?)
(a) 5.0 m/s
(b) 10 m/s
(c) 11 m/s
(d) 18 m/s
(e) She stops before she reaches the bottom.

Answer 1

Step-by-step explanation:

1. First draw a free body diagram of the scenerio (a block sliding down a a slant surface).
2. Then we analyze the forces and write equations that satisfy Fnet = ma. This will give us the acceleration as the block slides down the surface.

3. Last, we can use the kinematic equation (vf^2 = vi^2 + 2as) and to solve the final speed of the block.