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above the floor Now the ball is released from rest at a height of 3.00 meters Th

ID: 1784937 • Letter: A

Question

above the floor Now the ball is released from rest at a height of 3.00 meters The system is defined to be only the ball. M>, For the full motion from a height of 3.00 meters to just before hitting the floor, calculate the work done by the weight force. Show all your steps. 19. By how much did the potential energy change? PE = Explain your answer in words. 20. As the ball falls, the speed of the ball (circle one) increases decreases / stays the same and so the change in KE is (circle one) positive / negative / zero. energy.

Explanation / Answer

Given,

h = 3 m

18)The work done by the weight force is equal to the PE of the system

PE = m g h = 0.15 x 9.8 x 3 = 4.41 J

Hence, PE = 4.41 J

19)Delta PE = PEf - PEi

delta PE = 4.41 J - 0 = 4.41 J

Hence, delta PE = 4.41 J

20)Increases.

Change in KE is POSITIVE

21)As the ball falls, the speed increases since the decrease in potential energy is compensated by increase in Kinetic energy of the ball(from energy conservation principle)