The concepts of inertia and momentum are always confused because they have similar definitions. Inertia is the resistance of a body to motion, while momentum is the tendency of a body to move continuously.
What is Inertia?
This law states that a body remains at rest or in a state of motion until an effort or force is applied to cause it to change its position.
For example, when we push grass, it starts to drag on the ground. Otherwise the force used to change its position means that it is at rest and would remain at rest forever.
Another example, when a bob attached to a star is brought from its central position to one end, then released, it begins to oscillate around its central position.
Because it is so placed in the air chamber, there will be invisible air resistance to the pendulum. This will finally relieve Bob. So, this atmosphere acts as an external force.
Types of Inertia
According to the first law of Newton’s law of inertia, a body cannot change its position unless it is acted upon by an external force.
The inertia of a body is of three types:
- Inertia of rest
- Inertia of motion
-
Inertia of direction
Examples
Place a seal on the greased cardboard covering the sink. Tap a piece of cardboard with your finger quickly. The card slides away and the coin falls into the sink. This is due to the inertia of rest.
The plane travels a distance from the ground before taking off. This is because it has a fixed airfoil, which can result in lift if the aircraft and air have the same speed.
When the cutter pushes and sharpens the blade, the sparks fly along the tangent line of the blade due to a directional malfunction
What is Momentum?
The momentum of a body or object is a measure of the force of its contents. A quantity of movement in a body can be created or destroyed by the application of forces to it; However, its quality remains intact. It is therefore limited by the force required to stop the body for a given period of time.
When a ball and a boulder are thrown from the same height, and at the same time. We found that because the rock has more mass, it takes a lot more energy to stop it. This is why the stone keeps moving.
Difference Between Momentum and Inertia
| Momentum | Inertia |
| Momentum is a vector quantity as it is the tendency of a body to remain in motion. | Inertia is a scalar quantity as it is the resistance offered by the body to any change in its velocity. |
| Momentum is denoted as ‘p’. | Inertia is denoted as ‘I’. |
| The momentum of a body of mass ‘m’ moving with a velocity of ‘v’ is calculated as p=m×v | The inertia cannot be calculated using a formula. |
| Linear momentum and angular momentum are the two types of momentum. | The inertia of rest, inertia of motion, and inertia of direction are the three types of inertia. |
| Momentum depends on mass and velocity. | Inertia depends only on mass. |
| The total momentum is conserved. | Inertia has nothing to do with the conservation of energy. |
