Question

A person is pulling their luggage by the strap with an applied force at an angle as shown in the diagram.
What is the expression for the normal force acting on the suitcase?

• A. Weight
• B. Weight $+F_{applied}\sin \theta$
• C. Weight $-F_{applied}\sin \theta$
• D. Weight $+F_{applied}\cos \theta$
• E. Weight $-F_{applied}\cos \theta$

Answer 1

Answer: (C)

Weight $-F_{applied}\sin \theta$

FBD of the suitcase is shown in the figure.

Let the normal force acting on the suitcase be $N$.

Vertical direction : $F_{appplied}sin\theta +N=W$ $⟹N=W-F_{applied}sin\theta$