Difference Between Mass and Weight: The terms "Mass" and "Weight" are used synonymously in ordinary conversation, but the two words do not mean exactly the same thing. The difference between mass and weight is that mass is the amount of matter in a material, whereas weight is a measure of how the force of gravity acts upon that mass. Also, there are other aspects of differences based upon physical quantity, the gravitational effect, SI unit, measurement, etc. that will be discussed here.
But before directly jumping to know what are the differences between Mass and Weight it is essential to know what is Mass and weight and how they are related to each other.
What is Mass?
It is one of the basic quantities in Physics and the most essential property of matter. It can be defined as “The measure of the amount of matter in a physical body”. The SI unit of mass is Kilogram (kg).
What is Weight?
Weight can be defined as “The measure of the force acting on the object due to gravity”. The weight formula is-
w = mg
The SI Unit of Weight and Force are the same, that is, Newton (N). By seeing the expression above we can say that weight depends upon the mass and the acceleration due to gravity, the mass does not change but the acceleration due to gravity changes from place to place.
Relation Between Mass and Weight
Let us assume a body has a large mass and large weight. An example of this situation is a large object which is hard to throw because the weight of that object is large. Therefore, the relationship between weight and mass can be derived with the help of Newton’s second law which explains that the free falling object has an acceleration “g” as the magnitude.
Let the mass of the object be 1kg falls with an acceleration of 9.8m/s², then the magnitude of the force is given as-
F = ma
= (9.8 kgm/s² )
= 9.8 N
Therefore, it can be seen that the relation between weight and mass of an object with 1kg mass will have a weight of 9.8N.
Difference between Mass and Weight
After knowing what is mass and what is weight and their relationship let us know the differences between these two terms. The difference between Mass and Weight is that mass is the measure of inertia and weight is the measure of force. Based upon physical quantity, gravitational effects, SI unit, etc., here are some differences compiled below-
|Basis of Comparison||Mass||Weight|
|Definition||It is the measure of the amount of matter present in the body.||It refers to the measure of the amount of force that acts on mass because of the pull of gravity.|
|Mean||Mass is the measure of inertia.||Weigh is the measure of force.|
|Location||It stays the same everywhere, irrespective of location.||Weight will vary depending on the location.|
|Physical Quantity||Mass is a scalar quantity. It has magnitude.||It is a vector quantity. It’s got the magnitude and directs toward the Earth’s center or other gravity.|
|Gravitational Effect||It can never be zero.||It can be zero when no gravity is acting on it.|
|SI Unit||The SI unit of mass is the kilogram (kg).||Weight’s SI unit is Newton (N).|
|Measurement||We measure it using an ordinary balance such as beam balance, lever balance, or pan balance.||We can measure weight using a spring balance.|
|Denotation||‘m’ is used to denote Mass.||We use ‘w’ to denote weight.|
|Formula||To calculate mass, we use- mass = volume × density||The formula for calculating weight is- weight= mass × acceleration due to gravity|
How Much Do You Weigh on Other Planets?
While a mass of a person does not change elsewhere in the solar system, the acceleration due to gravity and weight varies considerably. The calculation of gravity on other bodies such as on Earth depends not just on mass but also on how far the "surface" is from the center of gravity.
On Earth, for example, your weight might be low at the top of the mountain than at sea level, if compared. The effect becomes even more drastic for large bodies, such as Jupiter. While the gravity exerted by Jupiter due to its mass is 316 times more than that of Earth but you would not weigh 316 times more because its surface is so far out from the center.
|Body||Multiple Earth Gravity||Surface Gravity (m/s²)|