Can an object be in equilibrium if there is only one force acting on it?

2 Answers
May 9, 2017

No: equilibrium requires forces to be balanced, so it requires (at least) two forces, unless there are zero forces acting.

May 10, 2017

No.

Explanation:

By definition, an object is in equilibrium when the sum of all forces acting on the object is zero.

This means the sum of vertical forces is zero, and the sum of horizontal forces is zero.

For example, we take one force acting on the object to be 1 newtons acting rightwards.

  1. The sum of vertical forces acting on the object will be 0 newtons.
  2. The sum of horizontal forces will be 1 newton to the right.

Since the sum of horizontal forces is not zero, the object is not in equilibrium.

Note: to be in equilibrium, the sum of torques acting on the object on each point must be zero too. This concept is similar to the one mentioned above.