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.

## Work Energy Theorem For A Variable Force

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.

**NCERT Class 11 Physics Book PDF Free Download**

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##### NCERT Class 11 Physics Hand Written Notes Chapter-Wise

**Chapter-1 (Physical World) PDF Free Download**

**Chapter-2 (Units and Measurement) PDF Free Download**

**Chapter-3 (Motion In A Straight Line) PDF Free Download**

**Chapter-4 (Motion In A Plane) PDF Free Download**

**Chapter-5 (Laws Of Motion) PDF Free Download**

**Chapter-6 (Work, Energy and Power) PDF Free Download**