题目内容：

1.A ball is thrown directly upwardswith an initial velocity of 20m/s.Determine the ball’s maximum height and thetime it will take for the ball to fall from its maximum height to the ground.(10 marks)
2.A man hauls a 20kg stone thatis currently resting atop a 300 meter cliff up the mountain side to a height of500 meters.He then casts the stone directly downwards until it reaches thevery base of the mountain (0 meters).What is the total work done on the stone?(Hint:work is the change ofenergy!) (10 marks)

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1.A ball is thrown directly upwards with an initial velocity of 20m/s.Determine the ball’s maximum height and the time it will take for the ball to fall from its maximum height to the ground.(10 mark...