Chapter 3, Problem 50R

To determine

The existence of action and reaction force pairs when an object falls towards earth if the air resistance is negligible.

Explanation of Solution

Introduction:

When an object falls towards the earth, the gravitational force acts in vertically downward direction.

The mathematical expression to evaluate the gravitational force when an object falls towards earth is,

  $F_G=mg$

Here,

• $m$ is mass of the object.
• $g$ is gravitational strength.

According to Newton’s third law, every object exerts equal force but in opposite direction. So, the earth will also exert the same amount of force on the objects too in the upward direction.

  $R_E=F_G$

Here,

• $R_E$ is reaction force exerted by earth on the object.

Conclusion:

Therefore, the gravitational force is exerted by object on earth and reaction force is exerted by earth on that object.