GRAVITATION

GRAVITATION

VERY SHORT ANSWER TYPE QUESTIONS (VSAQ)

1. Does the apple attract the Earth? Ans :- Yes, but the Earth’s movement is too small to see. 2. Why doesn't the E...

11. If the moon attracts the earth, why does the earth not move towards the moon? Ans :- Earth does not move towards...

21. What is buoyancy? Ans :- Buoyancy is the upward force exerted by a fluid on an immersed object. 22. What happen...

31. What causes an object to float? Ans :- The buoyant force is greater than the object's weight. 32. Name the forc...

SHORT ANSWER TYPE QUESTIONS (SAQ)

1. Why should we be sent flying in space if the force of gravity somehow vanishes today? Ans :- The centripetal forc...

2. Why is G called ‘a universal gravitational constant’? Ans :- The value of 𝐺 is the same for any pair of objec...

3. Why don’t we see the Earth moving toward an apple when it falls? Ans :- Although the apple does attract the Earth...

4. The volume of 50 g of a substance is 20 cm3 . If the density of water is 1g /cm3 , will the substance float or sink?...

5. You have a bag of cotton and anir on bar, each indicating a mass of 100 kg when measured on a weighing machine. In re...

6. How does the force of gravitation between two objects change when the distance between them is reduced to half? Ans...

7. If heavier bodies are attracted more strongly by the earth, why do they not fall faster to the ground? Ans :- Hea...

8. Explain the law of gravitation. Ans :- The law of gravitation states that every two objects in the universe attra...

9. What is the difference between weight and mass? Ans :- Weight is the force with which the Earth pulls an object d...

10. Describe buoyancy and how it affects floating and sinking objects. Ans :- Buoyancy is the upward force exerted b...

11. What did Newton realize about the force that makes the apple fall? Ans :- Newton realized that the same force pu...

12. What happens to a stone tied to a string when it is swung in a circle? Ans :- When a stone is swung in a circle,...

13. What happens to the reading on a spring balance when a stone is immersed in water? Ans :- When a stone is immers...

14. What do you understand by the gravitational force of earth and weight? Ans :- The gravitational force of the Ear...

15. What is the importance of the universal law of Gravitation? Ans :- The importance of universal law of gravitatio...

16. Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when h...

17. 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 i...

18. Explain Archimedes' principle in your own words. Ans :- Archimedes' principle states that when an object is plac...

19. Why do some objects float on water while others sink? Ans :- Objects float on water if their density is less tha...

20. Gravitational force on the surface of the moon is only 1/6 as strong as gravitational force on the earth. What is th...

21. Why is the weight of an object on the moon 1/6th its weight on the earth? Ans :- Since we know that F=m x g, t...

22. How does gravity vary across different locations on Earth? Ans :- Gravity is stronger at the poles and weaker at...

23. What is the significance of density in understanding why objects float or sink? Ans :- Density is crucial becaus...

24. State the universal law of gravitation. Ans :- According to Newton’s universal law of gravitation: Every mass in...

25. A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate (i) the maximum height to which it rises, (...

26. Can buoyancy be experienced by all objects in a fluid? Ans :- Yes, all objects experience buoyancy when immersed...

27. What is acceleration due to gravity and how is it different from acceleration? Ans :- Acceleration due to gravit...

28. What practical applications utilize Archimedes' principle? Ans :- Archimedes' principle has several practical ap...

29. What do you mean by acceleration due to gravity? Ans :- During free fall, any object with mass feels a force pul...

30. Why is it difficult to hold a schoolbag having a strap made of a thin and strong string? Ans :- It is hard to ca...

31. Why will a sheet of paper fall slower than one that is crumpled into a ball? Ans :- A larger surface area provid...

32. What are fluids? What are the factors on which the upward pressure at a point on a fluid depends? Ans :- Fluids...

33. Why does a block of plastic released under water come up to the surface of water? Ans :- Since plastic has a muc...

34. A force of 20N acts upon a body whose weight is 9.8N. What is the mass of the body and how much is its acceleration?...

35. Weight of a girl is 294 N. Find her mass. Ans :- W = mg 294 = m × 9.8 m = 30 kg

LONG ANSWER TYPE QUESTIONS (LAQ)

1. How does gravitational force affect the motion of objects like the Moon, the Earth, and an apple? Ans :- Gravitat...

2. A sealed tin of Coca Cola of 400 g has a volume of 300 cm3. Calculate the density of the tin. Ans :- Here, mass o...

3. What is the law of gravitation, and why is it considered universal? Ans :- The law of gravitation states that eve...

4. Explain the concept of buoyancy and Archimedes' principle. Ans :- Buoyancy is the upward force experienced by an...

5. Discuss how weight and mass are different concepts. Ans :- Weight and mass are two distinct but related concepts...

6. Why do some objects sink while others float in water? Ans :- Whether an object sinks or floats in water depends o...

7. Let us find force of attraction between two blocks lying 1 m apart. Let the mass of each block is 40 kg. Ans :- F...

8. What are some real-world applications of Archimedes' principle? Ans :- Archimedes' principle has various real-wor...

9. Calculate the force of gravitation due to a child of mass 25 kg on his mother of mass 75 kg if the distance between t...

10. A ball thrown up is caught by the thrower after 4 s. With what velocity was it thrown up? How high did it go? Where...

11. A sealed can of mass 600 g has a volume of 500 cm3. Will this can sink in water? Density of water is 1 g cm-3. Ans...

12. A force of 200 N is applied perpendicular to its surface having area 4 square metres. Calculate the pressure. Ans...

13. The density of water is 1000 kg m3. If relative density of iron is 7.874, then calculate the density of iron. Ans...

14. A particle is thrown up vertically with a velocity of 50 m/s. (a) What will be its velocity at the highest point of...

15. How much force should be applied on an area of 1 cm2 to get a pressure of 15 Pa? Ans :- Here, Area, A = 1 cm2 =...

NCERT SOLUTION

Page No. 102 1. State the universal law of gravitation. Ans:- The Universal La...

Page No. 104 1. What do you mean by free fall? Ans:- Free fall refers to the mo...

Page No. 106 1. What are the differences between the mass of an object and its weight?...

Page No. 109 1. Why is it difficult to hold a school bag having a strap made of a thin and...

2. What do you mean by buoyancy? Ans:- Buoyancy is the upward force exerted by a fluid (liquid or gas) on an obj...

3. Why does an object float or sink when placed on the surface of water? Ans:- An object floats or sink...

Page No. 110 1. You find your mass to be 42 kg on a weighing machine. Is your mass more or...

Page No. 111 1. How does the force of gravitation between two objects change when the distan...

2. Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall fast...

3. What is the magnitude of the gravitational force between the earth and a 1kg object on its surface? (Mass of the...

4. The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a...

5. If the moon attracts the Earth, why does the earth not move towards the moon? Ans:- i. Equal Gr...

6. What happens to the force between two objects, if (a) the mass of one object is doubled? (b) the distance betwee...

7. What is the importance of universal law of gravitation? Ans:- The universal law of gravitation explai...

8. What is the acceleration of free fall? Ans:- The acceleration of free fall is the acceleration experi...

9. What do we call the gravitational force between the Earth and an object? Ans:- The gravitational force between...

10. Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same whe...

11. Why will a sheet of paper fall slower than one that is crumpled into a ball? Ans:- A sheet of...

12. Gravitational force on the surface of the moon is only 1...

13. A ball is thrown vertically upwards with a velocity of 49ms -1. Calculate a) The maximum height to which it rises...

14. A stone is released from the top of a tower of height 19.6m. Calculate its final velocity just before touching th...

15. A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s 2, find the maximum hei...

16. Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth =6×10 24kg and...

17. A stone is allowed to fall from the top of a tower 100 m high and at the same time, another stone is projected ve...

18. A ball thrown up vertically returns to the thrower after 6s. Find (a) the velocity with which it was thrown up....

19. In what direction does the buoyant force on an object immersed in a liquid act? Ans:- The buoyant force on an...

20. Why a block of plastic when released under water come up to the surface of water? Ans:- A block of plastic ris...

21. The volume of 50 g of a substance is 20 cm 3. If the density of water is 1 g cm -3, will the substance float or s...

22. The volume of a 500 g sealed packet is 350 cm 3. Will the packet float or sink in water if the density of water i...

SUMMARY

Introduction In our studies, we have learned about how objects move and how forces cause that motion. A force is needed...

Gravitation 1. The Moon’s Orbit: The Moon travels around the Earth in a circular path. This motion is influenced by a f...

Centripetal Force 1. Definition: Centripetal force is the force that keeps an object moving in a circular path. It act...

Universal Law of Gravitation 1. What the Law Says: Newton’s law of gravitation explains that the force of gravity betw...

Importance of the Universal Law of Gravitation 1. Explains Why We Stay on Earth: The law explains that gravity is th...

Free Fall 1. What is Free Fall? Free fall happens when an object falls toward the Earth due only to the force of grav...

How to Calculate the Value of g 1. What is g? g is the acceleration due to gravity, which tells us how fast objects spe...

The motion of Objects under the influence of Gravitational Force of the Earth 1. Variation in the Value of g: The v...

Mass 1. What is Mass? Mass is a measure of how much matter an object contains. It tells us how much "stuff" is inside...

Weight 1. What is Weight? Weight is the force with which the Earth pulls objects toward it due to gravity. It depends...

Weight of an Object on the Moon 1. What is Weight on the Moon? Just like the Earth pulls objects towards it due to grav...

Thrust and Pressure 1. What is Thrust? Thrust is the force acting perpendicular to the surface of an object. For exam...

Pressure in Fluids 1. Fluids include Liquids and Gases: Both liquids and gases are called fluids because they can flo...

Buoyancy 1. Feeling Lighter in Water: When you swim in a pool, you feel lighter because of buoyancy. The water pushes...

Why Objects Float or Sink in Water 1. Understanding Density: Density is how much mass is packed into a certain volu...

Observations with the Stone in Water 1. Understanding the Activity: i. Materials Needed: A piece of stone, a rubber str...

Key Concepts in Gravitation and Buoyancy ❑ Law of Gravitation 1. Gravitational Attraction: The law of gravitation s...