Q: A juggler keeps four balls in air. Her throws each ball vertically upwards with the same speed at equal interval of time. The maximum height attained by each ball is 20 m. find kinetic energy of first ball when fourth ball is in hand. Assume that the mass of each ball is 10 g.
(a) 0.5 J
(b) 1 J
(c) 1.5 J
(d) 2.5 J
Ans: (a)