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. 1 only 2. None of the forces act on the chair since it is at rest. 3. 1 and 2 only 4. All three forces 5. 2 and 3 only

Answer 1

1 and 2 only gravitational force downward and upword force exerted by the floor

Answer 2

1 and 3 are correct only.

Explanation:

In case of '1', the forces will act on chair because force of gravity will work on it externally and in molecular level but it's reaction is work on the roof only not only chair.

According to Newton's their law of motion, the action and reaction always work on different bodies.

For, force exerted by the air due to its air pressure, the net resultant of all the forces will be zero. This is due to the pascal's law.

Net resultant of forces on a body submerged in a fluid is always zero due to the fluid.

Fluid is air in this case.