Mass vs Weight! Ever wondered what’s the difference between the two?
Mass and weight are usually used as one and interchangeably. This goes fine because we are living on Earth but if NASA’s expeditions go right then we may soon enough set up colonies on Mars or moon or any other suitable planet or satellite. Then we simply can’t interchangeably use mass and weight.
Do we have your attention? Good, now let us learn the difference between mass and weight, that is, mass vs weight in a simple and basic way.
Mass
Mass is defined as the measure of amount of matter present in a body. It is denoted as ‘m’. Mass of an object is always constant and is not influenced by any external forces and hence mass can never be zero.
There are many ways to calculate mass, one of the easiest ways of calculating mass is by using the following formula:
M = v*d
M = mass
V = volume
D = density
Mass is a scalar quantity meaning it has only magnitude but it doesn’t have a direction. The SI unit (International System of Units; Système International in French) of mass is kg or kilogram.
Weight
Weight is defined as the measure of amount of force which is acting on the mass due to the gravitational force. It is denoted by ‘w’. Weight doesn’t remain constant and it changes with the change in gravitational force.
There is only one way to calculate weight and we can calculate weight by the following formula:
W = m*g
W = weight
M = mass
G = acceleration due to the gravitational force
Weight is a vector quantity meaning it has both magnitude and direction. The SI unit of weight is Newton (N).
Now, that we have basic knowledge of what mass and weight is, we can move on to the differences between mass and weight
Mass vs Weight: Differences between the two
Mass is just a measure of amount of matter in an object whereas weight is a measure of amount of force acted upon mass due to gravitational force.
Mass is denoted as ‘m’ and weight is denoted as ‘w’.
Formula of mass is volume*density and formula of weight is mass*acceleration due to gravity.
Mass is a scalar quantity and weight is a vector quantity.
SI unit of mass is kg and that of weight is N.
Gravity has no influence on mass but weight is depended on the gravity.
Mass can never be zero but weight can be zero.
For example: Suppose you weigh 60 kilograms. When you are in space (zero gravity), your mass remains 60 kilograms but weight is zero because gravity is zero.
Mass can be measured using lever balance, beam balance, pan balance etc. weight can be measured using spring balance or via formula given above.
Weight on different celestial objects
As discussed above weight is totally dependent on gravity. As the gravity of celestial objects is different, your weight also will differ.
| Celestial Object | Multiple of Earth’s Gravitational Force | Gravitational Force |
|---|---|---|
| Sun | 27.9 | 274.1 |
| Mercury | 0.377 | 3.703 |
| Venus | 0.9 | 8.87 |
| Earth | 1 | 9.8 |
| Moon | 0.165 | 1.625 |
| Mars | 0.389 | 3.728 |
| Jupiter | 2.640 | 25.93 |
| Saturn | 1.139 | 11.19 |
| Uranus | 0.917 | 9.01 |
| Neptune | 1.148 | 11.28 |
Example: The gravity of Sun is 274.1. Suppose your mass is 60 kilograms. Then your weight will be (by using the formula)
Weight = mass*acceleration due to gravity
Weight = 60*274.1
Weight = 16,446 Newtons.
Is our weight the same on Earth?
No, our weight doesn’t remain same on Earth. Our weight differs when we go near the poles or to the equator. You would weigh 0.5% less at the equator than what you would weigh at the poles.
It happens because of two reasons. Centrifugal force is stronger at the equator than at the poles. Centrifugal force cancels gravitational force (very little). Apart from this, earth is bulged at the equator, the effect of gravitational force is lesser compared to the gravitational force at the poles.
However, this minor difference in weight is not considered except in physical experiments or physics problems. The gravitational force is 9.8 m/s.
Now that you have the explanation for mass vs weight, we hope it will help you with your school assignments!