# Mass and Weight

## Mass and Weight

What is Weight?

Weight is the measure of the force of gravity acting on a body,

The formula for weight it is given by:

Weight(W) = Mass(M) x Acceleration due to gravity(g)

As weight is a force its SI unit is also the same as that of force, SI unit of weight is Newton(N). The direction of the weight acts downwards towards the centre of the earth. It is sometimes also called as gravitational force (or) gravity.

What is Mass?

Mass is one of the fundamental quantities in physics and the most basic property of matter. We can define mass as the measure of the amount of matter in a body. The SI unit of mass is Kilogram (kg).

Mass depends on the number and composition of atoms and molecules.

Mass(m) = Weight(W)/Gravity(g).

The mass of a body does not change at any time. Only for certain extreme cases when a huge amount of energy is given or taken from a body. For example, in a nuclear reaction tiny amount of matter is converted into a huge amount of energy, this reduces the mass of the substance.

Mass and Weight Relation:

Weight(W) = Mass(M) x Acceleration due to gravity(g)

Mass is directly proportional to weight.

Thus, if mass increases weight increases and vice versa, if mass decreases weight also decreases.

Difference between Mass and Weight:

 Mass Weight Mass can never be zero. Weight can be zero. As in space if no gravity acts upon an object, its weight becomes zero. Mass is commonly measured in kilograms and grams. Weight is commonly measured in Newton’s. Mass doesn’t change according to location. Weight varies according to location. Mass is a scalar quantity. It has magnitude. Weight is a vector quantity. It has magnitude and is directed toward the centre of the Earth or other gravity well.