A pencil of mass M and length L has a moment of inertia about its center of mass of (1/12) M L²(assume uniform mass distribution). It balances vertically on the eraser in a state of unstable equilibrium. A fly of mass m is perched on the other end. Assuming the fly hangs on and the eraser does not slip, the kinetic energy of the system just before it hits the desk is A) (M + m)gL. B) 1/2(2M + m)gL. C) 1/2(M + m)gL. D) 1/2(M + 2m)gL. E) 2(M + m)gL.

Question

Quizplus · Accepted Answer

The Answer of A pencil of mass M and length L has a moment of inertia about its center of mass of (1/12) M L²(assume uniform mass distribution). It balances vertically on the eraser in a state of unstable equilibrium. A fly of mass m is perched on the other end. Assuming the fly hangs on and the eraser does not slip, the kinetic energy of the system just before it hits the desk is A) (M + m)gL. B) 1/2(2M + m)gL. C) 1/2(M + m)gL. D) 1/2(M + 2m)gL. E) 2(M + m)gL.

A Pencil of Mass M and Length L Has a Moment