Handwrit/e and show all work and steps

66 and 67 Conservation of Mechanical Energy 31. 33. 35. 37. 39. (I) A novice skier, starting from rest, slides down an icy frictionless 8.0 incline whose vertical height is 105 m. How fast is she going when she reaches the bottom? (II) A sled is initially given a shove up a frictionless 23.0" incline. It reaches a maximum vertical height 1.22 m higher than where it started at the bottom. What was its initial speed? (II) A spring with k = 83 N/m hangs vertically next to a ruler. The end of the spring is next to the 15-cm mark on the ruler. If a 2.5-kg mass is now attached to the end of the spring, and the mass is allowed to fall, where will the end of the spring line up with the ruler marks when the mass is at its lowest position? (II) A 1200-kg car moving on a horizontal surface has speed v = 85 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is the spring stiffness constant of the spring? (II) A vertical spring (ignore its mass), whose spring constant is 875 N/m, is attached to a table and is compressed down by 0.160 m. (a) What upward speed can it give to a 0.380-kg ball when released? (b) How high above its original position (spring compressed) will the ball fly? 68 and (-3!) Law of Conservation of Energy 47. (I) A 16.0kg child descends a slide 2.20 m high and, starting from rest, reaches the bottom with a speed of 1.25 m/s. How much thermal energy due to friction was generated in this process? 49. (II) A 145-g baseball is dropped from a tree 12.0 m above the ground. (a) With what speed would it hit the ground if air resistance could be ignored? (b) If it actually hits the ground with a speed of 8.00 m/s, what is the average force of air resistance exerted on it? 51. (II) A skier traveling 11.0 m/s reaches the foot of a steady upward 19" incline and glides 15 m up along this slope before coming to rest. What was the average coefficient of friction? 53. (II) A 66kg skier starts from rest at the top of a 1200mlong trail which drops a total of 230 m from top to bottom. At the bottom, the skier is moving 11.0 m/s. How much energy was dissipated by friction? 610 Power 57. 59. 61. 63. 65. 67. (I) How long will it take a 2750-W motor to lift a 385-kg piano to a sixth-story window 16.0 m above? (I) An 85kg football player traveling 5.0 m/s is stopped in 1.0 s by a tackler. (a) What is the original kinetic energy of the player? (b) What average power is required to stop him? (II) An outboard motor for a boat is rated at 35 hp. If it can move a particular boat at a steady speed of 35 km/h, what is the total force resisting the motion of the boat? (II) A driver notices that her 1080kg car, when in neutral, slows down from 95 km/h to 65 km/h in about 7.0 s on a flat horizontal road. Approximately what power (watts and hp) is needed to keep the cartraveling at a constant 80 km/h? (II) A 975kg sports car accelerates from rest to 95 km/h in 6.4 s. What is the average power delivered by the engine? (II) A pump lifts 27.0 kg of water per minute through a height of 3.50 m. What minimum output rating (watts) must the pump motor have