Question

Joe pulls with 25N of force on the rope. He gets the box moving and then reduces his pull to 20N. What happens to the box? Describe the motion of the box.

A. The box moves at a constant speed.
B. The box accelerates.
C. The box slows down and stops.
D. The box moves in the opposite direction

Answer 1

If Joe reduces his pull force to 20N and the box encounters friction, it will slow down and eventually stop, which corresponds to answer choice C.

Step-by-step explanation:

When Joe pulls with a force of 25N and gets the box moving, he then reduces his pull to 20N. According to Newton's first law of motion, an object in motion will stay in motion at a constant velocity unless acted upon by a net external force. Since Joe maintains his pull, albeit at a reduced force, and if we assume the surface has some friction, the box will most likely slow down due to the reduced force being unable to overcome the frictional force as effectively as the initial 25N. The correct answer is C. The box slows down and stops if the 20N force isn't enough to counteract the frictional force.