Question

a box filled to the top with rocks is sitting in the center of a flatbed truck. as the truck
lerates to the east, the box moves with it,
not sliding on the bed of the truck.
in what direction is the friction force ex-
erted by the bed of the truck on the box?

Explanation:

Step1: Analyze the box's motion

The box moves east with the truck. According to Newton's second law \(F = ma\), the box has an east - ward acceleration.

Step2: Determine the force causing acceleration

Since the only horizontal force acting on the box (assuming no air resistance etc. relevant here) is the friction force from the truck bed. For the box to accelerate east, the friction force must provide the east - ward force.

Answer:

The friction force is exerted in the east direction.