Work Energy Theorem

It state that work done by the net force acting on a body equal to the change produced in the kinetic energy of the body.

Work Energy Theorem For A Constant Force

When a force F acting on a body of mass m produces acceleration a in it. After covering distance s, let the velocity of the body changes from u to v.

Now, we use the equation of motion.

Let a variable force F acts on a body of mass m and produces displacement ds in its own direction i.e θ = 0.

If the applied force increases the velocity from u to v, then the total work done on the body will be

This proves the work energy theorem for a variable force.