work power energy jee mains notes

Important Formulas in Work Energy and Power for JEE

1. Work Done by Constant Force

W = FS cos Ө

It is a scalar quantity

2. Work done by Multiple Forces

W = W1 +W2+W3+….

Work done on the particle is the sum of the individual work done by all the forces acting on the particles.

3. Dimensions of work

Work = [ML²T^-2]

4. Kinetic Energy

As mass is a positive quantity kinetic energy is a positive quantity.

K = ½ mv²= p²/2m

p is the linear momentum

5. Potential Energy

F = -dU/dx for conservative forces

U_{Gravitational} = mgh

U_spring =(1/2) kx²

6. Work energy theorem

According to the theorem, the change in kinetic energy of a body is the net work done by the net force on the body

W= ∆K

7. Mechanical energy

Mechanical energy E of an object or a system is the sum of kinetic energy K and potential energy U.

E= U+K. Conserved if forces are conservative in nature

8. Power

P_av = W/t ,

Here W is the work done and t is the time taken