Which of the following is NOT in equilibrium?
A)a rock resting on the ground
B)a rock sliding at constant velocity across a frictionless surface
C)a rock rotating in place on a frictionless surface
D)a rock rotating at a constant rate as it slides at constant velocity across a frictionless surface
E)a rock falling off a cliff

Question

Quizplus · Accepted Answer

Equilibrium means the object has a net force of zero and is either at rest or moving with constant velocity. A rock falling off a cliff is not in equilibrium as it is accelerating due to gravity. Choices A, B, C, and D are all situations where the rock is in equilibrium.

Which of the Following Is NOT in Equilibrium