Chapter 9: Gravitation Short Questions | science Class 9 CBSE

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Chapter 9: Gravitation Short Questions | science Class 9 CBSE | ByteNotes.in

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Question 1

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Q1. Define gravitation.

It is the force of attraction between any two objects in the universe.
It acts along the line joining their centers.
It is a universal force.

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Question 2

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Q2. Write the universal law of gravitation.

F = G(M × m)/d²
Where F = force, G = gravitational constant, M and m = masses, d = distance.
It applies to all objects.

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Question 3

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Q3. What is the value of 'g' on Earth?

Approximately 9.8 m/s².
It is the acceleration due to gravity.
Varies slightly with location.

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Question 4

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Q4. Define mass.

Mass is the amount of matter in a body.
It remains constant everywhere.
Measured in kilograms (kg).

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Question 5

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Q5. What is the formula for weight?

Weight (W) = mass (m) × acceleration due to gravity (g).
W = mg.
Unit is newton (N).

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Question 6

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Q6. Define thrust.

Thrust is the force acting perpendicular to a surface.
It can change pressure.
Measured in newtons.

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Question 7

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Q7. What is pressure?

Pressure = force / area.
Measured in pascal (Pa).
Smaller area increases pressure.

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Question 8

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Q8. State Archimedes’ principle.

An object immersed in fluid experiences buoyant force equal to fluid’s weight displaced.
Explains floating and sinking.
Used in hydrometers.

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Question 9

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Q9. What is buoyant force?

An upward force exerted by a fluid on an object immersed in it.
It opposes gravity.
Varies with fluid density.

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Question 10

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Q10. Why do objects appear lighter in water?

Due to upward buoyant force from water.
Part of object’s weight is balanced by fluid.
Net weight is reduced.

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Chapter sections

Chapter 9: Gravitation | Short Questions

Q1. Define gravitation.

Q2. Write the universal law of gravitation.

Q3. What is the value of 'g' on Earth?

Q4. Define mass.

Q5. What is the formula for weight?

Q6. Define thrust.

Q7. What is pressure?

Q8. State Archimedes’ principle.

Q9. What is buoyant force?

Q10. Why do objects appear lighter in water?