Mass and Weight - UNSOLVED PRACTICE SET
Chapter: Gravitation | Topic: Mass and Weight
MASS AND WEIGHT - UNSOLVED PRACTICE SET
Topic: Mass and Weight
Multiple Choice Questions
Q1. Weight of an object is defined as:
- The amount of matter in the object
- The force of gravity acting on the object
- The volume occupied by the object
- The density of the object
Q2. A student's mass on Earth is 50 kg. What is her mass on the Moon?
- 50/6 kg ≈ 8.3 kg
- 50 × 6 = 300 kg
- 50 kg (mass does not change)
- Zero, because there is no gravity on the Moon
Q3. The SI unit of weight is:
- Kilogram (kg)
- Newton (N)
- Joule (J)
- Pascal (Pa)
Q4. An astronaut weighs 800 N on Earth. What is her approximate weight on the Moon? (gMoon = g/6)
- 800 N
- 4800 N
- 133 N
- 0 N
Q5. Which of the following quantities changes when you move from Earth to space?
- Mass
- Weight
- Both mass and weight
- Neither mass nor weight
Q6. A weighing machine (spring balance) placed in a free-falling lift will show:
- Normal weight
- Double the weight
- Zero (apparent weightlessness)
- Half the weight
Short Answer Questions
Q7. Distinguish between mass and weight. Give two key differences in a tabular format or as two clear points.
Q8. Why is the weight of an object zero at the centre of the Earth? Use the concept of gravitational force in your answer.
Q9. A bag of rice is labelled '5 kg' in a supermarket in Delhi. A tourist buys the same bag and takes it to a market on the Moon. Will the shopkeeper on the Moon measure the same 5 kg on a weighing scale? Explain.
Q10. Write the formula for weight (W) in terms of mass (m) and acceleration due to gravity (g). A student of mass 40 kg stands on a weighing machine. What reading (in Newtons) will the machine show?
Q11. Why do we sometimes loosely say 'my weight is 60 kg' when scientifically that statement is incorrect? What should we say instead, and why does the incorrect term persist in daily life?
Q12. Explain what 'apparent weightlessness' means. When does a person on Earth feel lighter than their actual weight inside a moving vehicle?
Long Answer Questions
Q13. Describe the relationship between mass, weight, and gravity in detail. Explain:
(i) how weight is calculated from mass,
(ii) what happens to your weight on the Moon, Mars, and in deep space,
(iii) why mass is a more fundamental quantity than weight, and
(iv) give a practical everyday example where this distinction matters.
Q14. A small child asks you: 'If I go to the Moon, will I be able to jump higher? Will I feel lighter? Can I lift heavier things?' Answer all three questions scientifically using the concept of mass, weight, and gravity. Make sure your explanation would be understandable to the child.
Q15. Discuss weightlessness. Explain:
(i) the physical meaning of weightlessness,
(ii) how astronauts in the International Space Station (ISS) experience weightlessness even though Earth's gravity is still present there,
(iii) what effect does long-term weightlessness have on the human body, and
(iv) how this relates to the concept of free fall.
Numerical / Application-Based Problems
Q16. A school bag has a mass of 8 kg.
(i) What is its weight on Earth?
(ii) What would be its weight on the Moon?
(iii) What is its mass on the Moon? State the formula used for weight.
Q17. An astronaut has a mass of 75 kg on Earth.
(i) Calculate her weight on Earth.
(ii) Calculate her weight on the Moon (g_Moon = g_Earth / 6).
(iii) If she lands on a planet where g = 15 m/s²,
calculate her weight there. Which planet could this be?
Q18. During a science fair, a group of Class 9 students sets up a spring balance. They hang a 2 kg stone from it.
(i) What reading does the spring balance show in Newtons on Earth?
(ii) If the same spring balance is carried to the Moon, what will it show?
(iii) If the stone is placed on a beam balance instead, will the Moon reading be the same as on Earth? Why?