Chapter 4.3, Problem 30PP

To determine

To Draw: The free body diagram of suitcase cart system.

Explanation of Solution

Introduction:

Free body diagram depicts the forces acting on a body in different directions. In any system, two forces acting with same magnitude and in opposite direction on different bodies are called an interaction pair.

Two separate systems are considered in this problem.

The suitcase-Cart system

Suitcase applies force ${\text{F}}_{\text{sc}}$ ,which is the weight of it, on the cart in the downward direction, as a reaction to this cart applies a force ${\text{F}}_{\text{cs}}$ on the suitcase in the upward direction. Since these two forces are equal in magnitude and act on different bodies in opposite direction, they are an interaction pair of forces.

The cart-ground system

The weight of the suitcase ${\text{F}}_{\text{sc}}$ in the downward direction, the weight of the cart ${\text{F}}_{\text{cg}}$ in the downward direction and the force by ground on the cart ${\text{F}}_{\text{gc}}$ in the upward direction are the forces in this system.

Conclusion:

The free body diagram of suitcase and cart are separately given below.

  

The force on the cart by the suitcase and force by the cart on the suitcase are the interaction pair.