Energy

The energy of a body is defined as it’s capacity or ability for doing work.

Like work, energy is a scalar quantity having magnitude only but no direction.

It’s dimensional formula is [ML²T⁻²].

It is measured in the same unit as work that is Joule in SI and erg in CGS system.

Energy can exist in various form such as Mechanical Energy (Potential Energy + Kinetic Energy), sound energy, heat energy, light energy etc.

Kinetic Energy

The energy possessed by a body by virtue of its motion is called Kinetic energy. In other words, the amount of work done i.e a moving object can do before coming to rest is equal to its kinetic energy.

Example:- A bullet fired from a gun can pierce a target due to its kinetic energy.

Notes

1. Kinetic energy of a body is always positive, it can never be negative.

2. Kinetic energy of a body depends upon the frame of reference.

Example:- Kinetic Energy of a person of mass m sitting in a train moving with velocity v is (1/2*m* v²) in the frame of earth and Kinetic Energy of the same person = 0 in the frame of the train.

Measurement Of Kinetic Energy

Let a body is initially at rest and the force F is applied on the body to displace it through ds along the direction of the force, then

Relation Between Kinetic Energy and Linear Momentum

NCERT Class 11 Physics Book PDF Free Download

Kinetic Energy

Notes

Measurement Of Kinetic Energy

Relation Between Kinetic Energy and Linear Momentum

Also Read

NCERT Class 11 Physics Hand Written Notes Chapter-Wise

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