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Most Important Selected Qs for JEE AdvancedPhysicsRotational Motion

A rod is free to rotate in horizontal plane about one of its end hinged at point 'O' as shown in figure. Point P & Q are fixed points located ir horizontal plane in such away that PO is perpendicular to rod & QO is along length of rod. A bullet hits the rod perpendicularly at some distance from point ' O ' and gets imbedded into it. Then :

Options

  1. ALinear momentum of rod + bullet system will decrease after collision.
  2. BLinear momentum of rod + bullet system may increase
  3. CAngular momentum of rod + bullet system about point ' P ' will not change before & after collision.
  4. DAngular momentum of rod + bullet system about ' Q ' may increase after collision.

Correct answer

D. Angular momentum of rod + bullet system about ' Q ' may increase after collision.

Step-by-step solution

Force applied by hinge on rod may be towards P , away from P or zero depending upon distance from point ' O '. Accordingly linear momentum of rod + bullet system may decrease increase or remains constant respectively. Similarly angular momentum of system about ' Q ' may decrease, increase or remain constant respectively.

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