5. A skier traveling 12.0 m/s reaches the foot of a steady upward 18 incline and glides 15.2 m up along this slope before coming to rest. What was the average coefficient of friction? 6. A 230-kg roller coaster reaches the top of the steepest hill with a speed of 5.80 km/h. It then descends the hill, which is at an angle of 45 and is 51.0 m long. What will its kinetic energy be when it reaches the bottom? Assume pk = 0.16. J 9. A 0.48-kg ball is thrown vertically upward with an initial speed of 14.5 m/s. What is the speed of the ball when it has travelled one-half of the distance to its maximum height? m/s 10. The drawing shows a version of the loop-the-Ioop trick for a small car. The radius of the |00p r = 0.42 m. What is minimum initial speed ('0) that the car needs to have in order to remain in contact with the circular track at all times? m/s / \"\\ l\\ Wm'k-LJ 1. A 5.2kg box slides a distance of 13.5-m. If the coefficient of kinetic friction is 0.33, what is the work done by the friction force? J