Class 9 Science MCQ Gravitation

Question : When a mango falls from a mango tree then
(a) only the Earth attracts the mango.
(b) only the mango attracts the Earth.
(c) both the mango and the Earth attract each other.
(d) both the mango and the Earth repel each other.

Question : School bags have a broader base to reduce
(a) pressure
(b) weight
(c) air resistance
(d) normal reaction

Question : In the relation F = G × M × m/d², the quantity G :
(a) depends on the value of g at the place of observation
(b) is used only when the earth is one of the two masses
(c) is the greatest on the surface of the earth
(d) is of the same value irrespective of the place of observation

Question : The SI unit of pressure is
(a) Nm²
(b) N/m
(c) N/m²
(d) N²/m²

Question : The constant G
(a) is a very small quantity
(b) is a force
(c) is the same as g
(d) decrease with increasing altitude

Question : According to one of the Kepler’s laws of planetary motion :
(a) r² ∞ T³
(b) r ∞ T²
(c) r³ ∞ T²
(d) r³ ∞ 1/T²

Question : Acceleration due to gravity varies with
(a) height
(b) depth
(c) shape of the planet
(d) all of these

Question : What is buoyant force-
(a) An upward force on an object immersed in a liquid
(b) Partially downward force
(c) A down ward force on an object immersed in a liquid
(d) None of the above.

Question : A sharp edge blade is more effective in cutting than a blunt blade due to
(a) Low force
(b) Low pressure
(c) Large contact area
(d) Small contact area

Question :A planet moving around sun sweeps out area A₁in two days, A₂in three days and A₃ in six days. Then the relation between A₁, A₂and A₃is

(A)3A₁ = 2A₂ = A₃
(b)2A₁ = 3A₂ = 6A₃
(C)3A₁ = 2A₂ = 6A₃
(d)6A₁ = 3A₂ = 2A₃.

Question :If a planet existed whose mass was twice that of Earth and whose radius 3 times greater, how much will a 1 kg mass weigh on the planet?
(a)25 N
(b)2.17 N
(C)1.1 N
(d)5 N

Question :Choose the correct statement.
(a)Weight is a vector quantity.
(b)The weight of a body in interplanetary space is maximum.
(C)Weight increases when the bodies go up.
(d)1 N = 1 kg m s^–1

Question :A balloon of mass m is rising with an acceleration a. A fraction of its mass is detached from the balloon. Its acceleration will
(a)decrease
(b)increase
(C)remain the same
(d)none of these

Question :If the mass of the body on the surface of the earth is 50 kg, its mass at the centre of the earth is
(a)zero
(b)more than 50 kg
(C)less than 50 kg
(d)equal to 50 kg

Question :The mass of a body is measured to be 12 kgon the earth. If it is taken to the moon, its masswill be
(a)12 kg
(b)6 kg
(C)2 kg
(d)72 kg.

Question :The unit ofG/g is
(a)kg m^–1
(b)kg m^–2
(C)m²kg^–1
(d)m kg^–1

Question :Two identical copper spheres of radius R are in contact with each other. If the gravitational attraction between them is F, find the relation between F and R.
(a)F ∝ R⁴
(b)F ∝ R^3/2
(C)F ∝^R–2
(d)F ∝^R–4

Question :A particle is dropped from a tower 180 mhigh. How long does it take to reach the ground?
Take g = 10 m/s2.
(a)2 s
(b)6 s
(C)5 s
(d)8 s

Question :Relation between mass of body and its weight is
(a)w = mg
(b)w=m/g
(C)g = m – w
(d)w = m + g

Question :In figure, the line that joins a planet to the sun sweeps out areas A1, A2, A3 in times intervals6 weeks, 3 weeks and 2 weeks respectively. How are A1, A2, A3 related?

(A)A₁ = 3A₂ = 2A₃
(b)A₁ = 2A₂ = 3A₃
(C)2A₁ = A₂ = A₃
(d)A₁ = 3A₂ = A₃

Question : A ball is thrown vertically upwards. The acceleration due to gravity:
(a) is in the direction opposite to the direction of its motion
(b) is in the same direction as the direction of its motion
(C) increases as it comes down
(d) become zero at the highest point.

Question : When an apple falls from a tree:
(a) only earth attracts the apple
(b) only apple attracts the earth
(C) both the earth and the apple attract each other
(d) none attracts each other

Question : The weight of an object is :
(a) the quantity of matter it contains
(b) refers to its inertia
(C) same as its mass but is expressed in different units
(d) the force with which it is attracted towards the earth

Question : The earth attracts the moon with a gravitational force of 1020 N. Then the moon attracts the earth with a gravitational force of:
(a) 10–20 N
(b) 102 N
(C) 1020 N
(d) 1010 N

Question : The orbits of planets around the sun are:
(a) circular
(b) parabolic
(C) elliptical
(C) straight

Question : When the medium between two bodies changes, force of gravitation between them :
(a) will increase
(b) will decrease
(C) will change according to the environment
(d) remains same

Question : S.I. unit of G is :
(a) Nm2 kg–2
(b) Nm kg–2
(C) N kg2M–2
(d) Nkg m–2

Question : The value of G in S.I. unit is :
(a) 6.67 × 10–9
(b) 6.67 × 10–10
(C) 6.67 × 10–11
(d) 6.67 x 10–12

Question : Force of attraction between two bodies does not depend upon :
(a) the shape of bodies
(b) the distance between their centres
(C) the magnitude of their masses
(d) the gravitational constant

Question : A stone is dropped from the top of a tower. Its velocity after it has fallen 20 m is [Take g = 10 ms–2] :
(a) 5 ms–1
(b) 10 m s–1
(C) 15 m s–1
(d) 20 m s–1

Question : A body is thrown up with a velocity of 20 m/s. The maximum height attained by it is approximately:
(a) 80 m
(b) 60 m
(C) 40 m
(d) 20 m

Question : The value of universal gravitational constant:
(a) changes with change of place
(b) does not change from place to place
(C) becomes more at night
(d) becomes more during the day

Question : Law of gravitation is applicable for:
(a) heavy bodies only
(b) medium sized bodies only
(C) small sized bodies only
(d) bodies of any size

Question : When a space ship is at a distance of two earths radius from the centre of the earth, the gravitational acceleration is :
(a) 19.6 ms–2
(b) 9.8 m/s–2
(C) 4.9 m/s2
(D) 2.45 ms–2

Question :The value of acceleration due to gravity (g) on earth’s surface is :
(a) 6.67 x 10–11 Nm2 kg2
(b) 8.9 m/sec2
(C) 9.8 m/sec2
(d) none of these

Question : Weight of an object depends on :
(a) temperature of the place
(b) atmosphere of the place
(C) mass of an object
(d) none of these

Question : The S.I. unit of g is :
(a) m2/s
(b) m/s2
(C) s/m2
(d) m/s

Question : The universal law of gravitation was proposed by :
(a) Copernicus
(b) Newton
(C) Galileo
(d) Archimedes

Question : The weight of a body is 120 N on the earth. If it is taken to the moon, its weight will be about:
(a) 120 N
(b) 60 N
(C) 20 N
(d) 720 N

Question :What happens to the acceleration due to gravity with the increase in altitude from the surface of the earth?
(a) Increases
(b) Decreases
(C) First decreases and then increases
(d) Remains same

Question :The acceleration due to gravity
(a) has the same value everywhere in space
(b) has the same value everywhere on the earth
(C) varies with the latitude on the earth
(d) is greater on the moon due to its smaller diameter.

Question :Which of the following statements is/are correct?
1. Mass of an object is the measure of its inertia.
2. Heavier the object smaller is the inertia.
3. The mass of an object is variable.
(a) Only 1
(b) 1 and 3
(C) 2 and 3
(d) 1 and 2

Question :Which of the following statements is true?
(a) g is same at all places on the surface of earth.
(b) g has its maximum value at the equator.
(C) g is less at the earth’s surface than at a height above it or a depth below it.
(d) g is greater at the poles than at the equator.

Question :The gravitational force between two bodies varies with distance r as :
(a) 1/r
(b) 1/r2
(C) r
(d) r2

Question : Value of G on surface of earth is 6.673 × 10–11 Nm2 kg–2, then value of G on surface of Jupiter is :
(a) 12 × 6.673 × 10–11 Nm2 kg–2
(b)126.673× 1 0–11 Nm2 kg–2
(C) 6.673 × 10–11 Nm2 kg–2
(d) 66.673× 10–11 Nm2 kg–2

Question : A heavy stone falls:
(a) faster than a light stone
(b) slower than a light stone
(C) with same acceleration as light stone
(d) none of these

Question : Choose the correct statement :
(a) All bodies repel each other in then universe.
(b) Our earth does not behave like a magnet.
(C) Acceleration due to gravity is 8.9 ms–2
(d) All bodies fall at the same rate in vacuum.

Question : A stone is dropped from the roof of a building takes 4s to reach the ground. The height of the building is :
(a) 19.6m
(b) 39.2 m
(C) 156.8 m
(d) 78.4 m

Question : The value of G in year 1900 was 6.673 × 10–11 Nm2 kg–2, The value of G in the year 2007 will be :
(a) 6.673 × 10–9 Nm2 kg–2
(b) 6.673 × 10–10 Nm2 kg–2
(c) 6.673 × 10–2 Nm2 kg–2
(d) 6.673 × 10–11 Nm2 kg–2

Question : Order of magnitude of G in S.I. unit is :
(a) 10–11
(b) 1011
(C) 10–7
(d) 107

Question : The type of force which exists between charged bodies is
(a) only gravitational
(b) neither gravitational nor electrical
(C) only electrical
(d) both electrical and gravitational

Question : The acceleration due to gravity:
(a) has the same value everywhere in space
(b) has the same value everywhere on the earth
(C) varies with the latitude on the earth
(d) is greater on moon because it has smaller diameter

Question : If planet existed whose mass and radius were both half of the earth, the acceleration due to gravity at the surface would be :
(a) 19.6 m/sec2
(b) 9.8 m/s2
(C) 4.9 ms–2
(d) 2.45 m/s2

Question :Assertion :The value of acceleration due to gravity changes with the height, depth and shape of the earth.
Reason :Acceleration due to gravity is zero at the centre of the earth.

Question :Assertion :It is the gravitational force exerted by the sun and the moon on the sea water that causes to the formation of tides in the sea.
Reason :Gravitational force of attraction is a strong force.

Question :Assertion : Any two objects in the universe attract each other by a force called gravitational force.
Reason : The force of gravitation exerted by the earth is called gravity.

Question :Assertion :When distance between two bodies is doubled and also mass of each body is doubled, then the gravitational force between them remains the same.
Reason :According to Newton’s law of gravitation, force is directly proportional to the product mass of bodies and inversely proportional to square of the distance between them.

Question :Assertion :When a body is thrown up, the acceleration due to gravity at the topmost point is zero.
Reason :The acceleration due to gravity is always directed towards the centre of the earthfor a freely falling body.

Question :Assertion :Universal gravitationalconstant G is a scalar quantity.
Reason :The value of G is same through out theuniverse.

Question :Assertion :Kepler’s second law of planetarymotion is also known as Kepler’s law of areas.
Reason :The line joining the planet and the sunsweeps equal areas in equal intervals of time.

Question :Assertion :If we drop a stone and a sheet of paper from a balcony of first floor, then stone will reach the ground first.
Reason :The resistance due to air depends on velocity only.

Question : Assertion :A sheet of paper falls slower, than one that is crumpled in to a ball?
Reason :Sheet of paper has lesser weight than that is crumpled into a ball.