Question

If there is only one external force (or torque) acting on an object, it cannot be in equilibrium.

a) True
b) False

Answer 1

The statement is False. An object can still be in equilibrium even if there is only one external force acting on it.

Step-by-step explanation:

The statement is False.

In order for an object to be in equilibrium, it must satisfy two conditions:

1. The net external force on the object must be zero.
2. The net external torque on the object must be zero.

If there is only one external force (or torque) acting on an object, it can still be in equilibrium as long as the net force and net torque are both zero.

For example, consider a book resting on a table. The gravitational force pulling the book downward is countered by the normal force exerted by the table upward. These forces are equal in magnitude and opposite in direction, resulting in a net force of zero. The book is also not rotating, so the net torque is zero. Therefore, the book is in equilibrium even though there is only one external force acting on it.