Question

An empty office chair is at rest on a floor. Consider the following forces:. 1. A downward force due to gravity;. 2. An upward force exerted by the floor; and. 3. A net downward force exerted by the air. Which force(s) act on the office chair?. 1. None of the forces act on the chair since. it is at rest. 2. All three forces. 3. 1 only. 4. 1 and 2 only. 5. 2 and 3 only.

Answer 1

 4. 1 and 2 only.

1. the downward force is the force of gravity.

2. The upward force exerted is the Normal reaction from the floor.