Question

1. The work-energy theorem applies to changes in kinetic energy because....

   a-		forces applied over a distance change the position, therefore the object has some velocity, which implies kinetic energy.
   b-		forces applied over a distance change the position, therefore the object has some acceleration, which implies kinetic energy.
   c-		forces are a part of kinetic energy.
   d-		forces applied over a distance change nothing about the system so we have to study kinetic energy.

Answer 1

As work energy theorem = ∆K.E.

For change in kinetic we need change in speed which only possible with acceleration.

Only due to the presence of acceleration, velocity can change.

So, part (B) is correct.

In part (A) because applied force build up acceleration which leads to change in velocity not directly the force changes velocity.

Part(C) force and kinetic energy both are different thing they can't be similar.

PartD)

It is proved from Newton's second law that applied force develop accelerate not nothing.