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Question
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
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Solution
Given : m = 0.200 kg; v = 30 ms−1
(i) Shown in diagram alongside.
(ii) 3 seconds.
(iii) K.E. = `1/2` mv2 = `1/2xx(30)^2` = 90 J.
(iv) P.E. = K.E. = 90 J.
[By the law of conservation of energy]
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