Question

What is momentum?

Answer 1

We have seen that it is easier to stop a ball with smaller mass than a ball with a larger mass when they are moving at the same speed. Also , it is difficult to lift heavier objects like books as compared to paper. The factor which explains the above mentioned observations is called momentum.

Complete step-by-step solution:
Let us start with the definition of momentum: it is a quantity of measure of a moving body.
It can be expressed in terms of $p = mv$
Where, p= momentum
M=mass and
V= velocity.
Let us now know why it is written in terms of mass and velocity.
Let us reconsider the example about the ball mentioned in the hint. We see that there are 2 balls, one with a larger mass and another with a smaller mass. If these 2 balls are thrown with the same velocity we observe that it is easier to catch the ball with the smaller mass than the bigger one. But what if the balls were moving with different velocities? The results would be different.
Now let’s keep the mass of the balls constant and let ball ‘a’ move with a higher velocity as compared to ‘b’.it is easy to know that the ball ‘b’ can be easily catched. Thus we see momentum depends on both mass and velocity.
This act of difficulty to change the state of motion of objects is called as momentum

Note: 1) Momentum is a vector quantity. Its SI unit is Ns or kgm/s.
2) Total momentum of the system is always conserved.
3) its dimensional formula is $\left[ {{m^1}{L^1}{T^{ - 1}}} \right]$