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Question
Two billiard balls A and B, each of mass 50 g and moving in opposite directions with speed of 5 ms–1 each, collide and rebound with the same speed. If the collision lasts for 10–3 s, which of the following statements are true?
- The impulse imparted to each ball is 0.25 kg ms–1 and the force on each ball is 250 N.
- The impulse imparted to each ball is 0.25 kg ms–1 and the force exerted on each ball is 25 × 10–5 N.
- The impulse imparted to each ball is 0.5 Ns.
- The impulse and the force on each ball are equal in magnitude and opposite in direction.
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Solution
c and d
Explanation:
We are given that, m = 0.05 kg and v = 5 m/s
Hence we have initial momentum of each ball p = mv = 0.05 × 5 = 0.25 kg ms–1
After the collision, both balls will move in opposite directions
Hence, we have the final momentum of each ball p' = – mv = – 0.05 × 5 = – 0.25 kg ms–1
Now the impulse is the change in momentum,
Hence, I = p' – p = – 0.25 – 0.25 = – 0.5 kg ms–1.
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