6. You push a 12 kg block horizontally with a force of 20 N while a frictional force of 8 N works against you. How fast will the block be moving after 8 m?

7. You push on a 20 kg block with a force of 80 N for 10 m. If the block starts from rest and is moving at 8 m/s at the end of 10 m, how much energy was lost to friction?

8. A box of mass m = 12 kg is pulled by a force Fp = 40 N at an angle of = 40 . There is a coefficient of kinetic friction of = 0.24. The box starts from rest and slides along the horizontal floor a distance of 6 m. a. Find the work done by friction. b. Find the work done by the force . c. Find the speed of the box after 6 m.

9. A block is sliding across a floor with a coefficient of friction of 0.35. It comes to a rest in 12 m. How fast was the block initially sliding?