Definition Of Kinetic Energy

Definition Of Kinetic Energy


"The energy due to motion is called kinetic energy".
Kinetic Energy = 1 / 2 mv2(squre)

More About Kinetic Energy

Kinetic energy is
Proportional to mass of a body.
Proportional to the square of the velocity
If two bodies have same mass and different speeds, then the faster body has larger kinetic energy.
If two bodies have same speed, then the heavier body has the larger kinetic energy
S.I. unit of Kinetic energy = work done is joule.
W = F X S = (Force is measured in Newton and the displacement in meters).
Hence the work done = Newton X meter = 1 Joule. 

Example 1: Two bodies of same mass move with velocity 3m/s and 5m/s, then the second body has more kinetic energy.

Examples of Work

The energy of a moving vehicle. 
The energy of a rolling football. 

Solved Example on Kinetic Energy

A body of mass � kg moves velocity 2m/s then the kinetic energy of the body is

A. 1J 
B. 2J
C. 3J
D. 0.5J
Correct answer is A.


Step 1: Write down the equation of kinetic energy. K.E=1/2 mv^2 
Step 2: Insert the value of the mass and velocity=1/2�1/2�2^2
Step 3: Write down the final answer in joules.
Step 4: K.E. = 1j.

Related Terms: Energy | Power | potential Energy | work done