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JEE Main202127 Aug 2021Evening ShiftPhysicsCenter of Mass, Momentum and CollisionActual

A bullet of 10   g , moving with velocity v , collides head-on with the stationary bob of a pendulum and recoils with velocity 100   m   s - 1 . The length of the pendulum is 0 . 5   m and mass of the bob is 1   kg . The minimum value of v   in   m   s - 1 , so that the pendulum describes a circle. (Assume the string to be inextensible and g = 10   m   s - 2 )

Correct answer

400

Step-by-step solution

Final velocity of system (bullet + mass) should be = 5 g r Now M 5 g r = m ( v + 100 ) thus v = M m 5 g r - 100 = 500 - 100 = 400   m   s - 1 v = 400   m   s - 1

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