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JEE Main202125 Jul 2021Morning ShiftPhysicsCenter of Mass, Momentum and CollisionActual

A body of mass 2 kg moving with a speed of 4 m s - 1 makes an elastic collision with another body at rest and continues to move in the original direction but with one fourth of its initial speed. The speed of the two body centre of mass is x/10 . Find the value of x.

Correct answer

0

Step-by-step solution

p i = p f 2 × 4 = 2 × 1 + m 2 × v 2 m 2 v 2 = 6   … ( 1 ) By coefficient of restitution, 1 = v 2 - 1 4 ⇒ v 2 = 5   m   s - 1 by ( i ) m 2 × 5 = 6 m 2 = 1 . 2   kg v cm = m 1 v 1 + m 2 v 2   m 1 + m 2 v cm = 2 × 1 + 1 . 2 × 5 2 + 1 . 2 = 8 3 . 2 = 25 10 x = 25

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