A backpack is dragged directly across the floor by a handle with a force of 75 N. If friction acts on the backpack with a force of 25 N, what is the net force acting on the backpack?

Question

Quizplus · Accepted Answer

To determine the net force acting on an object, simply sum all of the forces acting on the object. In this question, the backpack has an applied force of 75 N and friction acts on the backpack with a 25 N force. Since they act in opposition to each other, they have opposite mathematical signs in the calculation below.
Net force = Applied force + Friction force
Net force = 75 N + (-25 N)
Net force = 50 N
Remember that friction is working against the applied force (in the opposite direction), so it is a negative value.

A Backpack Is Dragged Directly Across the Floor by a Handle