2019-03-01_Physics_Times

Kinetic energy is the energy possessed by a body by virtue of its motion.

Kinetic Energy of a body of mass ‘m’ moving with a velocity ‘v’is^2

1 1

(. )

2 2

KE mv  m v v

 

The kinetic energy of a person of mass m, sitting in a train moving with speed v, is zero in the frame of

train but

(^12)
2
mv in the frame of the earth.

For a two dimensional force F F i F j x y the force is said to be conservative if it satisfies the 3rd equation

Fy Fx

x y

 



 ^  

Fz (^0).

5. Kinetic Energy

6. Kinetic energy depends on frame of reference

7.Conservative and Non- Conservative Force

8. Potential Energy

Potential energy of a body is the energy possessed by a body by virtue of its position or configuration.

In case of conservative forces.

dU

F

dr

 

  

 

 P.E of a mass m in earth gravitational field is

U = mgh (when h<<R)

 P.E depends on frame of reference.