Question

A 3.0 kg block slides down an incline that makes an angle ? = 30?The coefficient of kinetic friction between the block and the incline is ?k = 0.3 If the incline is 3 m long:

1. Determine the work done by friction

2. Determine the work done by the normal force

3. Determine the work done by gravity

4. What is the total work done on the block?

5. If the block is given an initial speed of 5 m/s, what is the speed of the block at the bottom of the

incline?

Answer 1

5-

Conservation of energy.

Let intially block is at h = 3 sin30°

mgh + 0.5mu^2 = 0.5mv^2

9.8*3*sin30° + 0.5*5^2 = 0.5*v^2

Velocity at bottom v = 7.37 m/s