It is quantity of motion of a moving body
It is a product of mass and velocity
Momentum = Mass × Velocity
Momentum = m × v
Example
Suppose a person has a mass of 60 kg
He moves at a speed of 3 meters per second
What is Momentum
Mass = m = 60 kg
Velocity = v = 3 m/s
Momentum = Mass x Velocity
= 60 kg x 3 m/s
= 180 kg m/s
What is Unit of Momentum
It is kilogram meter per second or kg m/s
Explanation
We know that
Momentum = Mass x Velocity
Mass is measured in kg and Velocity in meter/second
So Momentum-kg m/s
Whose Momentum will be Higher-Heavy object or Light Object?
Momentum of heavier object will be higher
Since momentum is a product of Mass and Velocity
We can change momentum by increasing mass of object
Example 1
Suppose 2 balls are thrown at same velocity of 10 meters/second
One is tennis ball of 100 grams (0.1 kg) other is cricket ball of 600 grams (0.6 kg0
Which has higher momentum
Cricket ball will have higher momentum because it has higher mass
Explanation
Momentum of Tennis ball
= Mass x Velocity
= 0.1 x 10
=1 kg m/s
Momentum of Cricket ball
= Mass x Velocity
= 0.6 x 10
= 6 kg m/s
Momentum of Cricket bal is higher due to its higher mass
Whose Momentum is Higher-An object at Higher Speed or Lower Velocity?
Momentum of object moving at higher velocity will be higher
Since momentum is a product of Mass and Velocity
We can change momentum by increasing velocity of object
Example
A ball bowled by fast bowler hits a batsman and hurts him
But if same ball is bowled by a slow bowler hits a batsman it does not hurt
Why
Ans
It is because of higher momentum in case of fast ball
Explanation
In this case, mass of ball is same in both the case
However, velocity of ball is more in case it is bowled by fast bowler
So, momentum will also be more
Questions
NCERT Question 9 -
What is the momentum of an object of mass m, moving with a velocity v?
(a) (mv)
2
(b) mv
2
(c) ½ mv
2
(d) mv
NCERT Question 13 - A hockey ball of mass 200 g travelling at 10 m s–1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s–1. Calculate the magnitude of change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.
NCERT Question 18 - How much momentum will a dumbbell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take its downward acceleration to be 10 m s–2.
