Question

Shirley Bored sits in her seat in the English classroom. The Earth pulls down on Shirley's body with a gravitational force of 600 N. Describe the reaction force of the force of gravity acting upon Shirley.

A) The reaction force is the electromagnetic force.
B) The reaction force is the tension in the seat.
C) The reaction force is the force Shirley exerts on the Earth.
D) The reaction force is the normal force from the chair.

Answer 1

The reaction force to gravity acting on Shirley is the force she exerts on the Earth, which is equal in magnitude and opposite in direction to the Earth's gravitational force on her.

Step-by-step explanation:

The reaction force to Shirley Bored's weight due to Earth's gravity is the force Shirley exerts on the Earth. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. Therefore, as the Earth pulls down on Shirley with a gravitational force of 600 N, Shirley exerts an equal force of 600 N on the Earth in the opposite direction. This action-reaction pair involves forces of gravity, which are always equal in magnitude and opposite in direction regardless of the masses involved.