Question

What is mass? What is inertia? What is the relationship between mass and inertia? What has more inertia: a kitten or an elephant? Why?

Answer 1

Ans. Mass of a body refers to quantity or amount of the material that makes up the body. In other words, mass of a body is the total amount of the material which forms it. (However it is not the same as weight since, weight takes into account the gravity). Mass is a physical property which also has the ability to limit the movement of a body of a certain mass.

Inertia is the restriction or limitation of a body with a certain mass which can affect its motion. For example, if a body is in motion, it will remain in motion unless something or some force acts on it. Similarly the other way is also right, that is, if a body is at rest, then a force can only move it, or else it will continue to remain at rest.

The relationship between mass and inertia is directly proportional. It means if a body has small mass it will have lesser inertia, if the body has huge mass it will have more inertia. So inertia is directly related to mass.

Among a mouse and an elephant, an elephant has more mass than a mouse. So if a mouse and an elephant are pulled with a rope when they are at rest, it will be easier to pull the mouse than the elephant. This is because mouse has lesser mass and thus lesser resistance to motion. On the other hand, the elephant has higher mass and thus higher resistance to motion, so higher is its inertia. Thus elephant will have more inertia.