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Some real examples of the gravitational pull in action are dropping a ball from a height or jumping on a trampoline. There are many activities in day to day life which require the force of gravity, like the tides in the ocean and an apple falling from a tree.
The NCERT Exemplar for Class 9 Science teaches students about this topic in Chapter 10. With the provided solutions in this chapter, students are able to investigate the fundamental truth which states that every object in the Universe is attracted to each other. These phenomena are explained using Newton’s Law of Gravitation which states that the gravitational force between two masses is proportional to the product of their masses and inversely proportional to the square of the distance between them.
NCERT Exemplar Solutions is formulated by expert educators of Physics keeping accuracy in mind. It is framed following the latest CBSE Class 9 Science syllabus and each concept is explained through examples and rationale.
Question:1
Two objects of different masses falling freely near the surface of moon would
(a) have same velocities at any instant
(b) have different accelerations
(c) experience forces of the same magnitude
(d) undergo a change in their inertia
Answer: A
When a body is dropped near the surface of moon, it would be attracted by moon’s gravitational force.Question:2
The value of acceleration due to gravity
(a) is same on equator and poles
(b) is least on poles
(c) is least on the equator
(d) increases from pole to equator
Answer:
Ans. CQuestion:3
The gravitational force between two objects is F. If masses of both objects are halved without changing distance between them, then the gravitational force would become
(a)
(b)
(c) F
(d) 2 F
Answer:
Ans. AQuestion:4
A boy is whirling a stone tied with a string in a horizontal circular path. If the string breaks, the stone
(a) will continue to move in the circular path
(b) will move along a straight line towards the centre of the circular path
(c) will move along a straight line tangential to the circular path
(d) will move along a straight line perpendicular to the circular path away from the boy
Answer:
Ans. CQuestion:5
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 d3 respectively. Which of the following statement is correct?
(a) d1 > d2 > d3
(b) d1 > d2 < d3
(c) d1< d2 > d3
(d) d1< d2 < d3
Answer:
Ans. DQuestion:6
In the relation
(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 greatest at the surface of the earth
(d) is universal constant of nature
Answer:
DQuestion:7
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
Answer:
CQuestion:8
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 the earth
(d) is independent of mass and radius of the earth
Answer:
D Gravitational force is a fundamental force, and it comes because of the property of mass.
Question:9
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)
Answer:
BQuestion:10
The atmosphere is held to the earth by
(a) gravity
(b) wind
(c) clouds
(d) earth’s magnetic field
Answer:
AQuestion:11
The force of attraction between two unit point masses separated by a unit distance is called
(a) gravitational potential
(b) acceleration due to gravity
(c) gravitational field
(d) universal gravitational constant
Answer:
DQuestion:12
The weight of an object at the centre of the earth of radius R is
(a) zero
(b) infinite
(c) R times the weight at the surface of the earth
(d)
Answer:
AQuestion:13
An object weighs 10 N in air. When immersed fully in water, it weighs only 8 N. The weight of the liquid displaced by the object will be
(a) 2 N (b) 8 N (c) 10 N (d) 12 N
Answer:
AQuestion:14
A girl stands on a box having 60 cm length, 40 cm breadth and 20 cm width in three ways. In which of the following cases, pressure exerted by the brick will be
(a) maximum when length and breadth form the base
(b) maximum when breadth and width form the base
(c) maximum when width and length form the base
(d) the same in all the above three cases
Answer:
BQuestion:15
An apple falls from a tree because of gravitational attraction between the earth and apple. If F1 is the magnitude of force exerted by the earth on the apple and F2 is the magnitude of force exerted by apple on earth, then
(a) F1 is very much greater than F2
(b) F2 is very much greater than F1
(c) F1 is only a little greater than F2
(d) F1 and F2 are equal
Answer:
DQuestion:16
Answer:
When any particle performs circular motion, the centripetal force is required to change the direction of the velocity.Question:17
Answer:
The motion in the vertical direction, will not be affected by horizontal motion.Question:18
Answer:
The moon revolves around the earth.Question:19
Answer:
The value of gravity near the equator is less than the value of gravity near the pole.Question:20
Answer:
It is given that the weight of any person on the moon is about 1/6th that on the earth.Question:21
Calculate the average density of the earth in terms of g, G and R.
Answer:
The weight of an object is nothing but the gravitational force by the earth on that body.Question:22
The earth is acted upon by gravitation of Sun, even though it does not fall into the Sun. Why?
Answer:
The earth is acted upon by the gravitation of sun, this gravitational force provides needed centripetal force to the earth.Question:23
Answer:
The weight of an object is nothing but the gravitational force by earth on that body.Question:24
Answer:
By universal law of gravitation, we know that the force between two particles kept at a fixed separation will be proportional to product of their masses.Question:25
Answer:
The weight of an object is nothing but the gravitational force by earth on that body.Question:26
(a) A cube of side 5 cm is immersed in water and then in saturated salt solution. In which case will it experience a greater buoyant force? If each side of the cube is reduced to 4 cm and then immersed in water, what will be the effect on the buoyant force experienced by the cube as compared to the first case for water? Give reason for each case.
(b) A ball weighing 4 kg of density 4000 kgm-3 is completely immersed in water of density 1000 kgm-3 .Find the force of buoyancy on it.
Answer:
(a) Force of buoyancy in any liquid is equal to weight of displaced fluid.Now, we know the displaced volume, we can calculate force of buoyancy.
NCERT Exemplar Class 9 Science Solutions chapter 10 covers the following topics of interest:
Chapter wise solutions |
Concept Clarity – Explains gravitation in a simple, easy-to-understand way.
Step-by-Step Solutions – Detailed methods for both theory and numericals.
CBSE Aligned – Follows the latest syllabus and exam pattern.
Covers All Question Types – Includes MCQs, short, and long answer questions.
Real-Life Applications – Uses practical examples to explain concepts.
Boosts Problem Solving – Encourages logical and analytical thinking.
Expert-Curated – Prepared by qualified Physics educators.
Also, read - NCERT Solutions for Class 9
Chapter No. | Chapter Name |
Chapter 1 | Matter in Our Surroundings |
Chapter 2 | Is Matter Around Us Pure |
Chapter 3 | Atoms and Molecules |
Chapter 4 | Structure of The Atom |
Chapter 5 | The Fundamental Unit of Life |
Chapter 6 | Tissues |
Chapter 7 | Diversity in Living Organisms |
Chapter 8 | Motion |
Chapter 9 | Force and Laws of Motion |
Chapter 10 | Gravitation |
Chapter 11 | Work and Energy |
Chapter 12 | Sound |
Chapter 13 | Why Do We Fall ill? |
Chapter 14 | Natural Resources |
Chapter 15 | Improvement in Food Resources |
It helps us understand natural phenomena like falling objects, orbits of planets, tides, and how things stay on the ground.
No, the gravitational force depends on mass and distance between objects.
It states that every object in the universe attracts every other object with a force directly proportional to their masses and inversely proportional to the square of the distance between them.
Due to Earth’s gravitational pull acting on them.
Gravity provides the centripetal force needed to keep them moving in a circular path around Earth.
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