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The diagram shows a skateboarder starting to roll down a hill. Assume that the skateboard rolls with negligible friction. Diagram is not to scale. A skateboarder and his skateboard have a combined mass of ?6.4 kg. The skateboarder passes a point P that is 3.90 m above bottom of the hill with a speed of 1.25 mfs. What is the skateboarder's kinetic energy,r as he passes another point Q that is 1.15 m above the bottom of the hill? 0 2.12 x 103 J O 2.89 x 103 J O 2.13 x 103 J O 2.93 x 103 J Two frictionless dynamics carts (A and B) are rolling on a horizontal surface. Cart A, with a mass of 4.50 kg, is travelling at 3.20 m/s [W] when it overtakes and runs into a 2.70 kg cart B travelling at 2.00 m/s [W]. Cart A hits and sticks to cart B. After the collision, the two carts are moving together at a velocity of 2.75 m/s [W]. What is the change in the mechanical energy of this system as a result of the collision? O-1.53 J O-1.89 ) O-0.986 J -1.22 JA small engine, connected to a water pump, has an effective power output of 2.?5 x 102 w. The engine was used to pump 2.40 x 103 kg of water out of a basement that is 3.20 m deep. What is the minimum time required for the water to be removed? A 345 W winch motor is used to pull a 5?5 kg mass up an inclined plane. If the force exerted bv the winch to move the mass is 4.50 x103 N, how long will it take the winch to move the mass 25.0 m up the incline? Question 26 (1 point} If the motor of a construction crane can generate a power output of 65.0 kW. How long would it take to lift a 1.45 2-: 103 kg bucket of concrete from the ground to a floor that is 42.5 m above the ground