Physics: Difference Between Weight and Mass

Difference Between Weight and Mass

• Weight is the gravitational force exerted by a celestial body (e.g., Earth, Moon, Mars) on an object on its surface.
• Weight is measured in newtons (N).
• A person's weight varies depending on the gravitational force of the celestial body; for example, weight on Earth differs from weight on the Moon.

Understanding Mass

• Mass measures the amount of matter in an object.
• In everyday terms, mass is typically measured in grams (g) or kilograms (kg).
• Unlike weight, mass remains constant regardless of location; a mass of 65 kg on Earth is still 65 kg on the Moon or any other planet.

Weight Calculation

• On Earth, weight can be calculated by multiplying mass (in kg) by the gravitational acceleration (approximately 9.8 m/s²).
• Weight formula on Earth: Weight (N) = Mass (kg) x 9.8
• On the Moon, the gravitational acceleration is about 1.63 m/s².
• Weight formula on the Moon: Weight (N) = Mass (kg) x 1.63

Example Calculations

• For an individual with a mass of 65 kg:
  • Weight on Earth: 65 kg x 9.8 = 637 N
  • Weight on the Moon: 65 kg x 1.63 = 106 N
• The gravitational force exerted by Earth is considerably greater than that of the Moon.