State and prove the work-energy theorem or Show that work done by a moving body is equal to the change in K.E of the body.

Explanation: The work energy theorem states that work done on a body is equal to the net change in its energy.

Proof: Consider a body of mass m moving with an initial velocity u . Let a constant force F acting on a body changes its velocity to v . Let s  be the distance travelled. 

From the third equation of motion we get:

Final Answer: Hence proved the work - energy theorem.