Gravitation Class 9 Worksheet Science Chapter 9

Multiple Choice Questions

Q1: If the area of an object is less than the pressure acting on that object will be
(a) Less
(b) More
(c) Independent of area
(d) None of the above

Q2: Even though stone also attracts earth towards itself, earth does not move
(a) Because of greater mass of earth
(b) Because of lesser mass of stone
(c) Force exerted by stone is less
(d) Force exerted earth is large

Q3: Which of the statements is correct?
(a) Mass is constant and weight is variable
(b) Mass is variable and weight is constant.
(c) Both Mass and weight are variable
(d) Both Mass and weight are constant.

Q4: Weight of the object is:
(a) More at the equator and less at poles
(b) More at poles and less at equator
(c) Same at poles and equator
(d) Depend on Mass of the object

Q5: An object is put one by one in three liquids having different densities. The object floats with 1/9, 2/11 and 3/7 parts of their volumes outside the liquid surface in liquids of densities d₁, d₂ and d₃respectively. Which of the following statement is correct?
(a) d₁ > d₂ > d₃
(b) d₁ > d₂ < d₃
(c) d₁ < d₂ > d₃
(d) d₁ < d₂ < d₃ 

Q6: In the relation F = GM mld², the quantity G
(a) depends on the value ofg at the place of observation
(b) is used only when the Earth is one of the two masses
(c) is greatest at the surface of the Earth
(d) is universal constant of nature

Q7: Law of gravitation gives the gravitational force between
(a) the Earth and a point mass only
(b) the Earth and Sun only
(c) any two bodies having some mass
(d) two charged bodies only

Q8: The value of quantity G in the law of gravitation
(a) depends on mass of Earth only
(b) depends on radius of Earth only
(c) depends on both mass and radius of Earth
(d) is independent of mass and radius of the Earth

Q9: Two particles are placed at some distance. If the mass of each of the two particles is doubled, keeping the distance between them unchanged, the value of gravitational force between them will be
(a) 1/4 times
(b) 4 times
(c) 1/2 times
(d) unchanged

Q10: The atmosphere is held to the Earth by
(a) gravity
(b) wind
(c) clouds
(d) Earth’s magnetic field 

Fill in the blank

Crossword

Across

3. Quantity of matter contained in a body
4. The property due to which a body immersed in fluid experiences upward force.
5. Acceleration due to gravity of moon is how much time that of Earth
7. Whenever objects fall towards the Earth under gravitational force alone, we say that objects are in
8. The force with which a body is attracted towards the Earth
10. Force of gravitation due to Earth is called
11. Nature of gravitational force is always

Down

1. Force between two bodies due to their masses
2. Thrust on unit area
6. Mass per unit volume
9. SI unit of pressure

Very Short Answer Questions

Q1: A man of mass 60 Kg is standing on the floor holding a stone weighing 40 N. What is the force with which the floor is pushing him up?
Q2: State Archimedes Principle?
Q3: Why does a block of plastic released under water come up to the surface of water?
Q4: Why will a sheet of paper fall slower than one that is crumpled into a ball?
Q5: Why is it difficult to hold a schoolbag having a strap made of a thin and strong string?
Q6: What makes a body to float or sink in a liquid?
Q7: What is the importance of universal law of gravitation?
Q8: What happens to the force between two objects, if
(i) the mass of one object is doubled?
(ii) the distance between the objects is doubled and tripled?
(iii) the masses of both objects are doubled?
Q9: State the universal law of gravitation.
Q10: What do you mean by buoyancy?

You can access the solutions to this worksheet here.