A pencil balanced on its tip such that it does not move
A) has a zero moment of inertia.
B) is in unstable equilibrium.
C) has a net torque acting on it.
D) has a net vertical force.
E) is in stable equilibrium.

Question

Quizplus · Accepted Answer

A pencil balanced on its tip is in unstable equilibrium because any small disturbance can cause it to fall over. This situation does not imply zero moment of inertia, net torque, or net vertical force, and it is the opposite of stable equilibrium.

A Pencil Balanced on Its Tip Such That It Does