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A ball of mass `1 kg` strink a heavy platform, elastically, moving upwards with a velocity of `5 m//s`. The speed of the ball just begore the collision is `10 m//s` downwards. Then the impulse imparted by the platform on the ball is :- A. `15 N-s`B. `10 N-s`C. `20 N-s`D. `30 N-s` |
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Answer» Correct Answer - D `e = - ((v_(2) - v_(1))/(u_(2) - u_(1))) rArr 1 = - (5 - v_(1))/(5 - (-10)) = (v_(1) - 5)/(15)` `rArr v_(1) = 20 m//s` `:.` Impulse on ball `= m(vec(v) - vec(u)) = 1 xx [20 -(10)] = 30N-s` |
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