What Is The SI Unit Of Momentum

Momentum is the physical quantity that is also a vector quantity. Momentum has come up from its origin word “Moment”. When we hear the word “moment”, we get a little idea about the relation between time and some kind of motion, or we can say motion that is dependent on time.

Since the word “momentum” has been derived from the word “moment”, it has a similar sense to it. Momentum is one of the physical quantities in physics where there is one object and that object possesses some motion and that too in one particular direction at a particular time. This article has to deal with the SI unit of momentum. So, you must be thinking, what is the SI unit of momentum? Read the below sections to cover the entire momentum concept.

What Is Momentum?

Before asking, what is the SI unit of momentum? You should understand what kind of physical quantity momentum is in physics? Momentum is the further improvised derivation of the word called “moment.” Moment means at this particular time in simple terms. But here, momentum gets its origin from the moment because in momentum, there is one object that is not at rest, or we can say that it is moving. Now, the object that is moving will have some forces responsible or working behind it because it is in motion. That force is applied and left because it lasts only for a fixed duration. The force applied divided by the difference in time interval for an object will define its momentum.

Momentum = Mass Of The Object X Velocity Of The Object

p = m x v

To understand momentum in layman terms, let’s take one example.

Imagine two friends, Jack and Jill, were running on the zebra-crossing of the road. Jack weighed 32kgs, whereas Jill weighed 42kgs. Both of them were running across the zebra-crossing on traffic. Suddenly, the red light turned green. Vehicles started accelerating quickly towards them. Both of them are sprinting at the same speed. Who will get injured by the vehicle collision? 

The answer is Jill because Jill is heavier than Jack; thus, Jill will have more momentum than Jack. This momentum will cause the injury to Jill because the velocity was constant.

What Is Linear Momentum?

Linear momentum also comes under the hierarchy concepts of momentum. It is a vector quantity that deals only with the measurement of the motion of any objects, Linear momentum is described as the product of the mass of an object, m, and its velocity of the object, v. 

Consider an example of a cricket ball being thrown high up in the skies through the air to understand the working of linear momentum better. When you catch the cricket ball coming from a great height, you feel the ball’s momentum hit you. When you catch the ball, it pushes your hand back towards you. The momentum of the cricket ball gets transferred from the ball itself to the hands of the catcher. Because of which, you can see fielders drag back their arms a bit while catching a cricket ball so that the enormous momentum of the ball can dissolve without walloping them.

Linear momentum SI units are the same as the units of momentum. Linear Momentum units are made up of the combination of mass(kg) and the velocity possessed by the object(ms-1). 

The dimensional formula of Linear Momentum is represented by [M1L1T-1].

Principle of Conservation of Linear Momentum

The conservation of momentum principle says that two colliding objects in an isolated system have the same cumulative momentum before and after the collision. That is, momentum is not lost but transmitted between the two objects when they collide. Momentum is always reserved in a completely isolated system even if it collides. The momentum from the object is transferred into your surface at the point of collision when the object is struck at a wall, for example.

The nature of collision determines how momentum is transferred. Collisions can be classified as elastic, perfectly inelastic, or somewhat inelastic.

Solved Example On Linear Momentum

1. The linear momentum of a ball is 30 kgms-1 and the mass of the ball is 5kg only. Determine the velocity of the ball.

Given parameters are mass of the ball = 5 kg, the linear momentum of the ball = 40 kgms-1.

Linear momentum formula is, p = m x v;

v = p / m => v = 30 / 5 => 6ms-1 is the velocity of the ball.

Conclusion

While the Conservation of Momentum concept is most commonly associated with mechanics’ s side of physics, it is not limited to things within the physical range of perception (macroscopic objects). It also applies to atomic and subatomic particles, although derivations may differ for things moving at close to the speed of light or with negligible mass. Linear momentum has a definite role in determining the 2nd law of motion. Other than linear momentum, there is one another type of momentum, and that is angular momentum. An object that spins has angular momentum, while one that moves at a constant speed has linear momentum.