Mass Examples in Physics
Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Mass.
This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Physics.
Concept Recap
The amount of matter in an object; a measure of how much it resists acceleration.
How 'heavy' something feels when you try to push it, regardless of gravity.
Read the full concept explanation →How to Use These Examples
- Read the first worked example with the solution open so the structure is clear.
- Try the practice problems before revealing each solution.
- Use the related concepts and background knowledge badges if you feel stuck.
What to Focus On
Core idea: Mass tells you how hard it is to change an object's velocity.
Common stuck point: Mass is not the same as weight. Mass is constant; weight depends on gravity.
Worked Examples
Example 1
easyAn object has a weight of 49 \text{ N} on Earth where g = 9.8 \text{ m/s}^2. What is the mass of the object?
Solution
- 1 Recall the relationship between weight and mass: W = mg, where W is weight, m is mass, and g is gravitational acceleration.
- 2 Rearrange for mass by dividing both sides by g: m = \frac{W}{g}
- 3 Substitute values: m = \frac{49}{9.8} = 5 \text{ kg}
Answer
m = 5 \text{ kg}
Mass is a measure of the amount of matter in an object and remains constant regardless of location. Weight depends on the gravitational field, but mass does not.
Example 2
mediumAn astronaut has a mass of 75 \text{ kg}. What would their weight be on the Moon where g_{\text{moon}} = 1.6 \text{ m/s}^2? Compare this to their weight on Earth (g = 9.8 \text{ m/s}^2).
Practice Problems
Try these problems on your own first, then open the solution to compare your method.
Example 1
easyA net force of 30 \text{ N} accelerates an object at 6 \text{ m/s}^2. What is the mass of the object?
Example 2
easyA toolbox weighs 72 \text{ N} on a planet where g = 12 \text{ m/s}^2. What is its mass?