Momentum

We know that all moving objects possess momentum. Momentum of the body is defined as the product of its mass and the velocity.

Now let us see how kinetic energy of a body is related to its momentum.

Consider a body of mass 'm' moving with a velocity 'v'. Then, momentum of the body, p = mv

Substituting the value of v in eqn (1) we get,

Numericals

01. Calculate the kinetic energy of a body of mass 5 kg, which is moving with a velocity of 15m/s.

Solution:

Mass of the body (m) = 5kg

Velocity of the body (v) = 15m/s

Kinetic energy = 1/2mv²

Kinetic energy = 562.5 J

02. A dog of mass 20kg is running at a constant speed of 12m/s. Calculate the kinetic energy of the dog while it is running.

Solution:

Mass of the dog (m)=20kg

Velocity (v)=12 m/s