Difference Between Mass and Weight with Examples and Table
Mass and weight are two foundational concepts in Physics, often confused but fundamentally different in nature. Mass is the measure of the amount of matter present in a body, while weight is the force exerted on that mass due to gravity.
Understanding the correct distinction between them is crucial for solving Physics problems, interpreting real-life phenomena, and preparing for competitive exams. Both mass and weight play critical roles in mechanics, planetary science, and various experiments, making it important to grasp their definitions, formulas, and real-world implications.
What Is the Difference Between Mass and Weight?
Mass is an intrinsic property of an object and does not change regardless of its location. It simply tells us how much matter is present. In contrast, weight is a measure of how strongly gravity pulls on that mass. Because weight depends on gravity, it changes from planet to planet or if a body moves to space.
For example, a rock has the same mass whether it is on Earth, the Moon, or Saturn. However, its weight will be different on each due to the difference in their gravitational pull.
Key Formulas and Definitions
The formula connecting mass and weight is:
- Mass (m) is measured in kilograms (kg).
- Weight (W) is measured in newtons (N), a unit of force.
- Standard gravity on Earth: g = 9.8 m/s2 (rounded up from 9.80665 for most calculations).
| Parameter | Mass | Weight |
|---|---|---|
| Basic Definition | Amount of matter in a body | Force gravity exerts on that body |
| Physical Type | Scalar quantity | Vector quantity (has direction) |
| SI Unit | Kilogram (kg) | Newton (N) |
| Depends On Location? | No | Yes (varies with gravity) |
| Changes on Moon/Planets? | No | Yes |
| Can It Be Zero? | No | Yes (in space, free fall) |
How Much Do You Weigh on Other Planets?
Since weight depends on gravitational pull, your weight changes depending on the celestial body you are on. The gravity on planets and moons varies. Earth’s gravity is taken as the reference point (1). For example, the Moon has only about 1/6th of Earth's gravity, so you would weigh much less there, while on massive planets like Jupiter or the Sun, you’d feel much heavier.
Use the formula: Weight on Planet = Mass × Surface Gravity of the Planet.
| Celestial Body | Multiple of Earth Gravity | Gravity (m/s2) |
|---|---|---|
| Sun | 28 | 274 |
| Mercury | 0.378 | 3.7 |
| Venus | 0.907 | 8.87 |
| Earth (reference) | 1 | 9.80665 |
| Moon | 0.166 | 1.62 |
| Mars | 0.377 | 3.71 |
| Jupiter | 2.36 | 24.79 |
| Saturn | 0.916 | 10.4 |
| Uranus | 0.889 | 8.87 |
| Neptune | 1.12 | 11.15 |
Step-by-Step: Solving Mass and Weight Problems
- Read the question carefully and identify if you need to find mass or weight.
- Write down the given values (mass, weight, surface gravity).
- Choose the correct formula:
- For weight: W = m × g
- For mass: m = W / g - Plug in the known values and carry out the calculation.
- Always include the correct units (kg for mass, N for weight).
Example 1: Weight on Different Planets
Suppose your mass is 60 kg. On Earth, your weight is:
WEarth = 60 × 9.8 = 588 N
On the Moon, using g = 1.62 m/s2:
WMoon = 60 × 1.62 = 97.2 N
This shows why astronauts feel much lighter on the Moon.
Example 2: Mass Calculation from Weight
If an object weighs 196 N on Earth, its mass is:
m = W / g = 196 / 9.8 = 20 kg
Visual Comparison of Mass vs. Weight on Celestial Bodies
| Object/Location | Mass (kg) | Weight (N) |
|---|---|---|
| Human on Earth | 60 | 588 |
| Same Human on Moon | 60 | 97.2 |
| Same Human on Jupiter | 60 | 1487.4 |
Quick Recap: Key Points
- Mass never changes with location—weight does.
- Weight is always directed towards the center of the gravity source (e.g., planet center).
- Use newtons (N) for weight, kilograms (kg) for mass in calculations.
Practice and Next Steps
- Reinforce your learning by solving more physics numericals involving mass, weight, and gravity.
- To deepen your understanding, see Difference Between Mass and Weight and Gravity on Earth.
- Explore related concepts like Mass and Momentum or learn about Weightlessness in space.
- Practice step-by-step solutions for Physics problems on Vedantu's dedicated Physics course pages.
Mastering the basic difference between mass and weight sets a strong foundation for future topics in mechanics, gravitation, and even rocket science. Practice regularly and clarify every concept for a deeper understanding of the physical world.
FAQs on Mass and Weight – Definitions, Differences, and Formulas
1. What is the difference between mass and weight?
Mass is the amount of matter present in an object and remains constant everywhere, whereas weight is the force with which gravity pulls an object, which changes depending on location (such as Earth or Moon).
• Mass is a scalar quantity, measured in kilograms (kg).
• Weight is a vector quantity, measured in newtons (N), and calculated as W = m × g.
• Mass does not change with gravity; weight changes if gravity changes.
2. What is mass and weight with example?
Mass is the amount of matter in a body, measured in kilograms (kg). For example, a book has a mass of 2 kg. Weight is the gravitational force acting on its mass. On Earth, the same book’s weight is W = 2 kg × 9.8 m/s2 = 19.6 N.
3. How to calculate mass and weight?
To calculate weight: Use the formula W = m × g, where m is mass (kg), and g is acceleration due to gravity (9.8 m/s2 on Earth).
To calculate mass: Use m = W / g if weight and gravity are known. Always use SI units (kg for mass, N for weight).
4. What is the SI unit of mass and weight?
SI unit of mass is kilogram (kg).
SI unit of weight is newton (N).
1 newton = 1 kg × 1 m/s2.
5. Is mass and weight the same on Earth?
No, mass and weight are not the same on Earth. Mass remains constant but weight is dependent on local gravitational acceleration. Both have different definitions, units, and physical meanings.
6. Why does weight change but mass remains constant?
Mass depends only on the quantity of matter, which does not change. Weight depends on gravity, which varies from planet to planet. Therefore, your weight changes in different gravitational fields, while your mass remains unchanged.
7. What is the formula and relationship between mass and weight?
The relationship between mass and weight is:
• W = m × g, where W = weight (N), m = mass (kg), g = gravitational acceleration (m/s2).
• Rearranged: m = W / g.
8. What is an example showing weight on Moon vs Earth?
Example: A 60 kg person has:
• Weight on Earth = 60 × 9.8 = 588 N
• Weight on Moon = 60 × 1.63 = 97.8 N
Mass is 60 kg at both places, but weight drops to about 1/6th on the Moon due to lower gravity.
9. What instrument is used to measure mass and weight?
Mass is measured using a beam balance.
Weight is measured using a spring balance, as it depends on the force due to gravity.
10. Can an object have zero weight?
Yes, an object can have zero weight in a region where there is no gravity, such as in deep space (weightlessness), but its mass will remain the same.
11. What does it mean: weight is a vector and mass is a scalar?
Mass (scalar) has only magnitude; it is simply a number with units.
Weight (vector) has both magnitude and direction (towards the center of gravity).
12. How does gravity affect your weight on other planets?
Gravity on different planets is higher or lower than Earth’s, so your weight changes depending on the planet's gravitational pull.
• For example: On Jupiter, you weigh more; on Moon, you weigh much less, but your mass stays the same everywhere.
