A truck has a crate in its cargo bed. If the truck stops abruptly and the crate does not move, the direction of the frictional force that the floor of the cargo bed exerts on the crate is backward.

Question

Quizplus · Accepted Answer

The frictional force is always in the opposite direction of the motion of the object. In this case, the crate is not moving, so the frictional force must be in the opposite direction of the truck's motion, which is backward.

A Truck Has a Crate in Its Cargo Bed