Question

Discuss few points about Work energy theorem.

Also derive the equation for it​

Answer 1

Work Energy Theorem- According to work energy theorem work done by all the forces equal to change in kinetic energy.

$Wall=\delta \: KE \\ KEf - KEi$

$Wall = \frac{1}{2}m( {V}^{2}f+ {V}^{2}i)$

Now

${v}^{2} = {u}^{2} + 2as \\ {v}^{2} = {u}^{2} + 2( \frac{Fnet}{m})S$

${ {v}^{2} } - {u}^{2} = \frac{2}{m}(Fnet \: S)$

$\boxed{\frac{m}{2}( {v}^{2} - {u}^{2}) = Wall}$

•Work energy theorem is applicable for all kind of forces.

•Work done by all forces will be positive if speed of the body increases.

•It will be negative if speed of the body decreases.