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
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