# A mechanic pushes a 2.60 x 103-kg car from rest to a speed of v, doing 5,460 J of work in the process. During this time, the car moves 21.0 m. Neglecting friction between car and road, find v and the horizontal force exerted on the car. (a) the speed v m/s (b) the horizontal force exerted on the car (Enter the magnitude.) N A 0.25-kg stone is held 1.4 m above the top edge of a water well and then dropped into it. The well has a depth of 5.4 m. (a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone-Earth system before the stone is released? J (b) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone-Earth system when it reaches the bottom of the well? J (c) What is the change in gravitational potential energy of the system from release to reaching the bottom of the well? J

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i need help with these two questions!

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