Section A – Multiple Choice Questions (MCQs) [Q.1–20]
- The value of acceleration due to gravity (g) on Earth’s surface is approximately:
a) 6.67 × 10⁻¹¹ N m²/kg²
b) 9.8 m/s²
c) 3 × 10⁸ m/s
d) 1.6 m/s² - The force of attraction between two masses is directly proportional to:
a) Product of masses
b) Sum of masses
c) Difference of masses
d) Square of masses - The force of attraction between two masses is inversely proportional to:
a) Distance between them
b) Square of distance between them
c) Cube of distance between them
d) Their volume - The SI unit of gravitational force is:
a) Newton
b) Joule
c) Pascal
d) kg m/s - The universal gravitational constant (G) has units:
a) Nm²/kg²
b) Nm/kg²
c) N/kg
d) Nm²/kg - The value of G is:
a) 6.67 X 10-9 Nm²/Kg²
b) 6.67 X 10-11 Nm²/Kg²
c) 9.8 Nm²/Kg²
d) 10 Nm²/Kg² - Weight of a body is:
a) Same everywhere
b) Different at different places
c) Independent of gravity
d) Equal to mass - Mass of a body is:
a) Same everywhere
b) Different at different places
c) Zero at poles
d) Maximum at equator - Which of the following is a scalar quantity?
a) Force
b) Weight
c) Mass
d) Acceleration - If the distance between two objects is doubled, the gravitational force becomes:
a) Half
b) One-fourth
c) Double
d) Four times - The weight of an object on the Moon is:
a) Same as Earth
b) 1/6th of Earth
c) 1/2 of Earth
d) 6 times Earth - Density of Earth is related to:
a) Mass and volume of Earth
b) Radius of Earth
c) Mass only
d) None - The centripetal force needed for Earth’s revolution is provided by:
a) Friction
b) Gravitation of Sun
c) Atmosphere
d) Rotation of Earth - A ball thrown upwards returns back due to:
a) Centrifugal force
b) Gravitational force of Earth
c) Magnetic force
d) Friction - The acceleration due to gravity decreases with:
a) Altitude
b) Depth
c) Latitude
d) All of these - Which quantity remains constant everywhere?
a) Weight
b) Mass
c) g
d) None - Free fall is motion under the influence of:
a) Only air resistance
b) Only gravity
c) Only friction
d) Gravity + air - Escape velocity is velocity needed to:
a) Go to orbit
b) Escape Earth’s gravity
c) Fly in space shuttle
d) Move in atmosphere - The SI unit of pressure is:
a) N
b) N/m²
c) Nm²
d) Pascal/sec - Pressure in fluids is transmitted equally in all directions. This is:
a) Boyle’s Law
b) Pascal’s Law
c) Archimedes’ Principle
d) Newton’s Law
Section B – True/False [Q.21–30]
- Gravitation is a repulsive force. (False)
- The value of G changes with place. (False)
- Weight of an object is equal to mass × g. (True)
- Mass is constant everywhere. (True)
- Acceleration due to gravity decreases with altitude. (True)
- Acceleration due to gravity is maximum at equator. (False)
- Free fall is motion without air resistance. (True)
- Weight of an object on Moon is greater than on Earth. (False)
- Liquids exert pressure in all directions. (True)
- Upthrust is the upward force exerted by fluids. (True)
Section C – Fill in the Blanks [Q.31–40]
- The SI unit of gravitational constant is __________.
- The value of G is __________.
- The value of g on Earth’s surface is __________.
- Weight of a body = __________ × g.
- The force of gravity is always __________.
- Free fall occurs under the influence of __________.
- Escape velocity on Earth is about __________ km/s.
- Archimedes’ principle explains the concept of __________.
- Pascal’s law states that pressure in fluids is transmitted __________.
- Density = __________ / __________.
Section D – Assertion & Reason [Q.41–50]
- Assertion: Mass of a body changes with location.
Reason: Mass depends on gravity. - Assertion: Weight of a body decreases on Moon.
Reason: g on Moon is 1/6th of Earth. - Assertion: Gravitational force is inversely proportional to square of distance.
Reason: F ∝ 1/d². - Assertion: Gravitation is a short-range force.
Reason: It acts only at small distances. - Assertion: The value of G is universal.
Reason: It is constant everywhere in universe. - Assertion: Pressure in fluids increases with depth.
Reason: Pressure = hρg. - Assertion: Weightlessness is experienced in orbit.
Reason: Both satellite and astronaut fall freely towards Earth. - Assertion: Gravitational force between two bodies is attractive.
Reason: It acts along the line joining the centres of two bodies. - Assertion: Free fall acceleration is same for all bodies.
Reason: Acceleration due to gravity does not depend on mass. - Assertion: Earth’s gravity decreases with height.
Reason: Gravity ∝ 1/R².
Section E – Very Short Answer (1 Mark Each) [Q.51–60]
- Define gravitation.
- Write SI unit of G.
- Write value of G.
- Write formula for weight.
- What is free fall?
- Define acceleration due to gravity.
- Write value of g on Earth’s surface.
- What is escape velocity?
- Name the principle related to buoyant force.
- Define thrust.
Section F – Short Answer (2 Marks Each) [Q.61–70]
- Differentiate between mass and weight.
- Define universal law of gravitation.
- A body of mass 10 kg is on Earth. Find its weight.
- Why is mass constant but weight variable?
- Define upthrust with example.
- Why is g less at equator than at poles?
- Define density with formula and SI unit.
- Why do objects float on water?
- Define pressure with formula.
- Why do astronauts feel weightlessness in space?
Section G – Short Answer (3 Marks Each) [Q.71–80]
- State and explain universal law of gravitation.
- Derive expression for acceleration due to gravity.
- Write three differences between mass and weight.
- A ball of mass 5 kg has weight 49 N. Find g.
- A man weighs 600 N on Earth. Find his weight on Moon.
- Why is it easier to carry heavy loads on Moon?
- Explain factors affecting value of g.
- Define pressure in fluids.
- Explain Archimedes’ principle with example.
- Why do some objects sink and some float in water?
Section H – Long Answer (4–5 Marks Each) [Q.81–90]
- Derive the formula for force of gravitation.
- Derive expression for g = GM/R².
- A ball is thrown up with velocity 20 m/s. Find time of ascent, maximum height, and time of flight.
- Explain free fall with numerical example.
- Define acceleration due to gravity. Derive its expression.
- Derive Archimedes’ principle with example.
- Explain Pascal’s law with experiment.
- Define thrust and pressure. Give differences with examples.
- Why do astronauts feel weightless in satellite? Explain.
- Write four applications of Archimedes’ principle.
Section I – Case Study Based [Q.91–100]
Case Study 1 (Q.91–95):
A body of mass 2 kg is dropped from a height of 10 m.
- What is the force acting on the body?
- Find acceleration during fall.
- Find velocity just before hitting ground.
- Find time of fall.
- Define free fall.
Case Study 2 (Q.96–100):
A wooden block of mass 200 g floats in water.
- Which force acts upward on block?
- Name the principle involved in floating.
- If volume of block submerged is 100 cm³, find upthrust.
- Why does block float?
- Define relative density.