Difference Between Mass and Weight – GCSE Physics
Introduction
- To understand how things move, interact, and behave in the physical world, the concepts of Mass and Weight are studied.
What is Mass?
- Mass is how much matter is in an object.
- It is the property of physical objects that measures:
- Inertia: Resistance to acceleration when a force is applied.
- Gravitational influence: Shows the strength of attraction between two objects.
Key Points:
- SI Unit of Mass is Kilogram (Kg).
- It is a Scalar Quantity.
- Mass never changes no matter where the object is—on Earth, on the Moon, or in space.
- It measures Inertia.
Example:
A Rocket has a mass of 2,000 kg, whether it’s on Earth, the Moon, or floating in space, it’s still 2,000 kg.
In all Scenario the Mass of Rocket will remain same (e.g.,2,000 kg)
What is Weight?
- Measure of the Gravitational pull of an object.
- It depends on both the object’s Mass and the local Gravitational Acceleration.
Key Points:
- SI Unit of Weight is Newton (N).
- It is a Vector Quantity.
- It changes with gravity, so weight varies depending on where the object is (Earth, Moon, or space).
- It measures Gravitational force.
Example:
A person with a mass of 60 kg,
Difference between Mass and Weight
Calculating Mass and Weight
Formula for Mass:
Where,
- W = Weight
- g = Acceleration due to Gravity
Formula for Weight:
Where,
- m = Mass
- g = Acceleration due to Gravity
Solved Example
Solved ExampleProblem: A bag of rice has a weight of 49 newtons on Earth. What is the mass of the bag?
Solution:
Step #1: Given
- W = 49N
- Take gravitational acceleration,
g = 9.8 m/s2
Step #2: Using the formula:
Step #3: Putting the Values:
The mass of the bag of rice is 5 kilograms.
Final Answer: 5 kg
Solved Example
Problem: An object has a mass of 8 kilograms. What is its weight on Earth?
Solution:
Step #1: Given
- m = 8kg
- Take gravitational acceleration,
g = 9.8 m/s2
Step #2: Using the formula:
Step #3: Putting the Values:
The weight of the object is 78.4 newtons.
Final Answer: 78.4 N
Frequently Asked Questions
Solution:
Mass is how much matter you have. Weight is how strongly gravity pulls on that matter.
Solution:
Gravity is different on every planet. Your mass doesn’t change, but the force (weight) does.
Example: 60 kg mass
– Earth: 60 x 10 = 600 N
– Moon: 60 x 1.6 = 96 N
Solution:
Mass- Kilogram (kg)
Weight- Newton (N)
Solution:
Use W= m x g If you know your mass and the planet’s gravity, multiply them.
Example:
70 kg on Mars (g = 3.7)-70 x 3.7 = 259 N
Solution:
Weight is a force. Mass is how much matter you have.
Weight = gravity pulling on that matter.