A crate travels through a factory on a conveyor belt (without slipping) at a constant speed. The conveyer belt is inclined at some non-zero angle above the horizontal. If air resistance is negligible, what forces are active on the box?
A) normal force, weight, static friction, kinetic friction
B) normal force, weight, static friction
C) normal force, weight, static friction, force of the conveyor belt
D) normal force and weight

Question

Quizplus · Accepted Answer

The forces acting on the crate are the normal force (perpendicular to the surface of the conveyor belt), the weight of the crate (due to gravity), and static friction (which prevents the crate from slipping and allows it to move along with the conveyor belt). Kinetic friction is not involved since the crate is not sliding against the belt, and the force of the conveyor belt is essentially the static friction force that moves the crate along.

A Crate Travels Through a Factory on a Conveyor Belt