Mass Vs Weight: Definition, Relationship & Differences

mass and weight differences and relationship

In everyday language, the terms "mass" and "weight" are often used interchangeably. However, in the realm of physics and science, these two concepts have distinct meanings and implications. Mass and weight are fundamental properties that describe the characteristics of an object, but they differ in their definitions, measurements, and physical interpretations. This article aims to delve into the differences between mass and weight, shedding light on their significance and clarifying common misconceptions.


A mass of a body is the quantity of matter contained in that body. It has magnitude but no direction. Mass is an intrinsic property of matter and represents the amount of material present in an object. It is a scalar quantity that remains constant regardless of an object's location or external conditions. In simple terms, mass is a measure of how much "stuff" an object contains. The SI unit for mass is the kilogram (kg). 


This is a measure of the force of gravity of the earth on a body. It is a gravitational pull of the earth on any body towards its center. It is a vector quantity, I.e. it has magnitude as well as direction. It represents the gravitational force acting on an object's mass. Weight depends on the strength of the gravitational field in which an object is placed. The SI unit for weight is the newton (N), which is a derived unit representing the force required to accelerate a mass of one kilogram at a rate of one meter per second squared.

Relationship between mass and Weight

Weight of a body = Force
Force = mass of body x acceleration due to gravity
I.e. W = F =  mg
m = W/g

In this equation, the gravitational acceleration represents the strength of the gravitational field. On Earth's surface, the standard value for gravitational acceleration is approximately 9.8 meters per second squared (9.8 m/s^2). However, this value may vary slightly depending on the location and altitude.

It is important to note that weight can change based on the gravitational field strength, while mass remains constant. For example, an object that weighs 50 newtons on Earth would have the same mass as an object that weighs 50 newtons on the Moon. However, due to the Moon's weaker gravitational field, the object on the Moon would weigh less compared to its weight on Earth.


Find the weight of a ball if the mass of the ball is 10kg and the acceleration to gravity is 10m/s2.
W = mg
W = 10 kg x 10 m/s2
W = 100N

Difference between mass and Weight

  1. Mass is a measure of the amount of matter in an object, representing its inertia and remaining constant regardless of location or external conditions. Weight, on the other hand, is the force exerted on an object due to gravity, varying with the strength of the gravitational field.

  2. Mass is measured using a balance or scale, comparing the object's mass to a standard mass. Weight is measured using a spring scale or a weighing scale, which determines the force exerted by an object due to gravity.

  3. The unit of mass is the kilogram (kg), while the unit of weight is the newton (N).

  4. Mass is independent of gravity and remains constant. Weight, however, depends on the gravitational field strength and varies with different gravitational forces.

  5. Mass is an intrinsic property of matter and does not change with the object's location. Weight, on the other hand, is extrinsic and changes depending on the gravitational field strength.

  6. To calculate weight, you multiply an object's mass by the acceleration due to gravity. Weight = mass × gravitational acceleration. The formula for mass does not involve gravity.

  7. Mass is the same regardless of the location in the universe. Weight, however, differs depending on the gravitational field strength, such as on Earth, the Moon, or other celestial bodies.

  8. Mass is the same throughout an object, whereas weight can vary depending on the distribution of mass within the object.

  9. Mass determines an object's inertia and its resistance to changes in motion. Weight, on the other hand, affects the force required to move or lift an object against gravity.

  10. In the absence of air resistance, all objects, regardless of their mass, experience the same acceleration due to gravity. This means that objects of different masses will fall at the same rate, but their weights will differ due to their mass discrepancy.

Mass and weight - on moon

Weight on Earth: 100kg x 9.8m/s2 = 980N.

Weight on Moon: 100kg x 1.622 m/s2 = 162.2N.

Related Questions

1)  The mass of a rock on the Earth is 2.0 kg. What is the mass of the rock on the Moon?
A) 1.7
B) 2.0
C) 3.5
D) 20.0

2) Why is weight not equal everywhere?
A) Because of altitude.
B) Because of the varying mass other planets when compared with earth.
C) Because of force of gravity
D) All of the above
E) None of the above

3) An astronaut of mass 40 kg jumped out of the rocket after it had landed on Jupiter.  The astronaut took 0.40 s to drop for 2.0 m. What was the weight of the astronaut on Jupiter?
A) 500
B) 1000
C) 800
D) 2000

4) A student's weight on Earth is 100 pounds. If this student went to the Moon, what  would he weigh?
A) more
B) less
C) the same

Do you know any of the answers? If so share it or ask for it. Do you have any other mass and Weight related questions? Ask it and I will be happy to answer it or send you a detailed solution. Responses are within 24hrs.


Understanding the distinction between mass and weight is crucial for comprehending the fundamental principles of physics and scientific measurements. Mass represents the amount of matter contained in an object and remains constant, regardless of the object's location or external influences. On the other hand, weight is the measure of the force exerted on an object due to gravity and varies based on the strength of the gravitational field. While mass is measured using a balance, weight is measured using a spring scale or a weighing scale. It is essential to use these terms correctly to avoid confusion and misconceptions in scientific discussions and calculations.

By grasping the differences between mass and weight, we gain a deeper understanding of the nature of matter, forces, and the fundamental laws that govern our universe. Recognizing that mass is an intrinsic property while weight is influenced by gravity allows us to accurately describe and analyze physical phenomena.

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