A packing crate slides down an inclined ramp at constant velocity. Thus we can deduce that
A) a frictional force is acting on it.
B) a net downward force is acting on it.
C) a net upward force is acting on it.
D) it is not acted on by appreciable normal force.
E) it is not acted on by appreciable gravitational force.

Question

Quizplus · Accepted Answer

If the crate is sliding down an inclined ramp at constant velocity, it means that the force of friction acting on the crate is equal and opposite to the force pulling it down the ramp (most likely due to gravity). If there was no friction, the crate would slide down the ramp with increasing speed, and if there was a net upward force, the crate would slow down and eventually stop. Therefore, the presence of a constant velocity indicates the presence of a frictional force.

A Packing Crate Slides Down an Inclined Ramp at Constant