Exploring Forces Class 8 Curiosity Worksheet Answers PDF

Q1. Force is
a) friction b) pressure
c) power d) None of these

Answer: (d) None of these
Explanation: A force is a push or pull acting on an object. It is different from power (the rate of doing work), pressure (force acting per unit area), and friction (a specific type of force).

Q2. The force is always attractive in nature and extends to infinity
a) magnetic force b) gravitational force
c) frictional force d) electrostatic force

Answer: (b) gravitational force
Explanation: Gravitational force is the force of attraction between any two objects having mass. It is always attractive in nature and acts over very large distances, theoretically extending to infinity, although it becomes weaker with increasing distance.

Q3. Three objects 1, 2, and 3 of the same size and shape but made of different materials are placed in water. They dip to different depths as shown in figure. If the weights of the three objects 1, 2, and 3 are w1, w2, and w3, respectively, then choose the correct relation.
a) w1 = w2 = w3 b) w1 > w2 > w3
c) w3 > w1 > w2 d) w2 > w3 > w1

Answer: (b) w1 > w2 > w3
Explanation: Heavier objects sink deeper because their weight overcomes buoyant force more, while lighter ones float higher.

Q4. A spring balance is used for measuring
a) mass b) pressure
c) speed d) weight

Answer: (d) weight
Explanation: A spring balance measures the weight of an object. It works by measuring the force with which gravity pulls the object, causing the spring inside the balance to stretch.

Q5. Force changes the
a) speed of the body b) shape of body
c) all of these d) motion of the body

Answer: (c) all of these
Explanation: A force can produce several effects on an object. It can change its state of motion, increase or decrease its speed, and change its shape or size.

Q6. Why does a force disappear when interaction stops between two objects?
a) Objects move away from each other b) Objects change shape
c) Objects become heavier d) Interaction is necessary for force generation

Answer: (d) Interaction is necessary for force generation
Explanation: Forces exist only during the interaction between objects.

Q7. A ________ exerted by an object on another is a force.
a) Push or pull b) Pressure
c) Contact or non-contact force d) Magnitude

Answer: (a) Push or pull
Explanation: A force is defined as a push or pull exerted by one object on another. Whenever an object is pushed or pulled, a force acts on it.

Q8. Which two objects interact when you push a table?
a) Your hand and the table b) The chair and the table
c) The table and the floor d) Your hand and your arm

Answer: (a) Your hand and the table
Explanation: When you push the table, your hand and the table interact.

Q9. What is required for a force to act on an object?
a) The object must be heavy b) The object must be stationary
c) One object must be moving d) Two objects must interact

Answer: (d) Two objects must interact
Explanation: Forces result from the interaction between objects.

Q10. Which one of the following forces is a contact force?
a) Force of gravity b) Magnetic force
c) Electrostatic force d) Force of friction

Answer: (d) Force of friction
Explanation: Frictional force acts only when two surfaces are in contact with each other. Since physical contact is necessary for friction to occur, it is a contact force. Gravity, magnetic force, and electrostatic force can act without direct contact, so they are non-contact forces.

Q11. If you kick a ball on the ground, which objects are involved in the force?
a) The ground and the ball b) Your foot and the ball
c) The ball and the wall d) Your foot and the air

Answer: (b) Your foot and the ball
Explanation: Your foot applies a force to the ball.

Q12. What happens when balanced forces are acting on an object at rest?
a) The object changes color b) The object remains at rest
c) The object changes shape d) The object starts moving

Answer: (b) The object remains at rest
Explanation: Balanced forces keep an object at rest in its state.

Q13. Which of the following statements best explains the difference between mass and weight?
a) Weight changes depending on b) Mass decreases as objects heat up, location, while mass doesn't weight increases
c) Mass varies with gravity, weight d) Both are completely interchangeable doesn't

Answer: (a) Weight changes depending on location, while mass doesn't
Explanation: Unlike mass, weight is dependent on the gravitational pull, which can vary.

Q14. What unit is used to measure the weight of an object?
a) Gram b) Kilogram
c) Meter d) Newton

Answer: (d) Newton
Explanation: The weight of an object is measured in newton (N).

Q15. The force exerted by the Earth to pull the object towards itself is called
a) muscular force b) contact force
c) gravitational force d) electrostatic force

Answer: (c) gravitational force
Explanation: The Earth attracts all objects towards its center due to gravity. The force responsible for this attraction is called gravitational force. It acts without direct contact between the Earth and the object, making it a non-contact force.

Q16. The force exerted by an animal’s body is called
a) mechanical force b) gravitational force
c) magnetic force d) muscular force

Answer: (d) muscular force
Explanation: Animals use their muscles to perform activities such as pulling, carrying, running, and lifting. The force produced by the muscles of an animal's body is called muscular force.

Q17. During dry weather, while combing hair, sometimes we experience hair flying apart. The force responsible for this is
a) force of gravity b) electrostatic force
c) magnetic force d) force of friction

Answer: (b) electrostatic force
Explanation: When a comb is rubbed through dry hair, electric charges build up on the comb and the hair. These charges exert an electrostatic force on the hair strands, causing them to repel each other and fly apart.

Q18. How would you measure weight using a spring balance?
a) Hang an object and observe the b) Attach the object to a pendulum stretching of the spring platform
c) Place the object on a scale d) Fill a container with water and place the object inside

Answer: (a) Hang an object and observe the stretching of the spring
Explanation: When an object is hung from a spring balance, the stretching of the spring indicates the weight.

Q19. When a book is resting on a table, how many objects are interacting?
a) Four b) One
c) Two d) Three

Answer: (c) Two
Explanation: The book and the table are interacting through gravitational force.

Q20. Which device can be used to measure the weight of an object?
a) Pedometer b) Barometer
c) Thermometer d) Spring balance

Answer: (d) Spring balance
Explanation: A spring balance is used to measure the weight of an object.

Q21. Assertion (A): A force can bring about a change in the direction of an object in motion.
Reason (R): Hitting a moving ball with a bat changes its direction.
a) Both A and R are true and R is the b) Both A and R are true but R is not the correct explanation of A. correct explanation of A.
c) A is true but R is false. d) A is false but R is true.

Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: Applying force to a moving object can alter its course, exemplified in sports.

Q22. Assertion (A): Water has the ability to exert force in a vertical direction.
Reason (R): When an object is placed in water, the force of buoyancy always acts downwards.
a) Both A and R are true, and R is the b) Both A and R are true, but R is not the correct explanation of A. correct explanation of A.
c) A is true, but R is false. d) A is false, but R is true.

Answer: (c) A is true, but R is false.
Explanation: Buoyant force acts upwards, counteracting gravity.

Q23. Assertion (A): Pumice can float on water because it is porous and filled with air pockets.
Reason (R): Pumice has a density higher than that of water due to its formation process.
a) Both A and R are true, and R is the b) Both A and R are true, but R is not the correct explanation of A. correct explanation of A.
c) A is true, but R is false. d) A is false, but R is true.

Answer: (c) A is true, but R is false.
Explanation: Pumice floats because it is less dense than water.

Q24. Assertion (A): A force can change the shape of an object.
Reason (R): Applying pressure to an inflated balloon changes its shape.
a) Both A and R are true and R is the b) Both A and R are true but R is not the correct explanation of A. correct explanation of A.
c) A is true but R is false. d) A is false but R is true.

Answer: (a) Both A and R are true and R is the correct explanation of A.
Explanation: Applying pressure or force can alter the shape of objects, as seen with balloons.

Q25. What is muscular force and in what situations do we apply it?

Answer: Muscular force refers to the force exerted by the muscles of the body. It is applied when performing activities like walking, running, jumping, or lifting objects.

Q26. How does the downhill speed without pedaling relate to gravitational pull as a form of force?

Answer: Gravitational pull causes the bicycles to accelerate downhill, demonstrating gravity's force.

Q27. What symbol is used to represent the unit of force, and what is the standard unit called?

Answer: The standard unit of force is called newton, represented by the symbol 'N'.

Q28. Name two effects a pushing force can have on an object.

Answer: A pushing force can change the direction of a moving object or cause it to deform, e.g., hitting a ball or pressing clay.

Q29. Define contact forces. Give two examples of contact forces.

Answer: Contact forces require physical interaction between two objects. Examples include muscular force and friction.

Q30. How does a pull affect a stationary object? Give an example.

Answer: A pull can affect a stationary object by causing it to move, such as pulling a toy car with a string.

Q31. Is any force being applied to an object in a non-uniform motion?

Answer: Yes, a force is applied to an object in non-uniform motion (when speed or direction changes). Force causes these changes, like speeding up, slowing down, or turning.

Q32. What is the scientific term used to describe a push or pull applied to an object?

Answer: The scientific term for a push or pull applied to an object is called 'force'.

Q33. Why do ships have specific shapes to move through water?

Answer: Ships are shaped specifically to reduce water resistance or friction, allowing them to glide more easily through water.

Q34. How does friction depend on the surface?

Answer: Friction varies based on the roughness of the surface; it is higher on rough surfaces and lower on smooth surfaces.

Q35. Using the concept of force interaction, explain why a book kept on a table does not slide on its own.

Answer: A book remains stationary on a table because of the static frictional force acting upwards at the point of contact, balancing the gravitational pull downwards. This interaction ensures no net movement.

Q36. Describe an everyday action that demonstrates the interaction of force between two objects and identify the forces involved.

Answer: Driving a car involves various interactions like the engine applying force to propel the vehicle forward, while the tires apply force on the road surface, showing interaction-induced forces at play.

Q37. Why is it easier to slip on a wet surface?

Answer: Wet surfaces have less friction compared to dry surfaces. Friction is the force that helps in gripping the ground when walking or moving. When a surface is wet, the thin layer of water reduces the irregularities between the surfaces of shoes and the floor, causing the friction to decrease. With less friction, it is easy to slip and fall.

Q38. Define buoyant force and explain how it affects an object placed in a liquid.

Answer: Buoyant force is the upward force exerted by a fluid on an object placed in it. It affects the object by counteracting the downward gravitational force. If the buoyant force is greater than or equal to the object's weight, the object will float. Otherwise, the object will sink if the gravitational force is stronger.

Q39. In what way do forces change if the interaction between objects shifts in direction? Provide an example.

Answer: If you push a door sideways, the force applied changes direction and influences the door's swing accordingly. Changing the force direction alters the interaction results, demonstrating forces' dependency on direction.

Q40. Why do we sometimes slip on smooth surfaces like ice or polished floors? Explain.

Answer: We slip on smooth surfaces because there is very little friction between our feet and the surface. Without enough friction to grip and oppose sliding, it's easy to lose balance and fall.

Q41. Explain the relationship between buoyant force and gravitational force when an object is submerged in a liquid.

Answer: When an object is submerged in a liquid, the buoyant force works upward, while the gravitational force acts downward. If the forces are equal, the object floats. However, if the gravitational force surpasses the buoyant force, the object sinks.

Q42. What happens when you try to pull a mug out of the water while it's inside the bucket, and why does it feel lighter?

Answer: The mug feels lighter when lifted inside water because it experiences upthrust or buoyant force exerted by the water, which acts in the upward direction. This upward force reduces the net downward force acting on the mug, making it feel lighter.

Q43. How do objects like aeroplanes utilize designs to overcome frictional forces?

Answer: Aeroplanes are designed with streamlined shapes to reduce air resistance, enabling them to move efficiently through the air by minimizing friction. Additionally, their smooth surfaces and aerodynamically shaped wings help decrease drag further, allowing the engines’ thrust to overcome the remaining frictional forces and maintain speed.

Q44. What happens when someone cycles against the wind?

Answer: When someone cycles against the wind, it becomes difficult because the wind pushes against them, requiring more effort to move forward.

Q45. Devise an experiment to demonstrate the effects of magnetic force on non-magnetic materials and outline what you expect to observe.

Answer: An experiment to demonstrate the magnetic force involves placing a wooden block (non-magnetic) on a table with small paperclips (magnetic) scattered around. Introduce a strong magnet beneath the table's surface, moving it slowly. Expect to see the paperclips respond to the magnetic force by moving about, attracted and following the magnet's path, while the wooden block remains unaffected, highlighting the non-magnetic nature of the wood.

Q46. Explain why weight can vary while mass remains constant on different planets.

Answer: Weight is the measure of gravitational pull on an object, and this force varies among different planets due to varying gravitational fields. For example, while a 1 kg mass remains constant on Earth, the weight changes-10 N on Earth, 3.8 N on Mars-because Mars has a weaker gravitational force than Earth. Mass remains unaffected by location, as it measures the amount of matter in an object, while weight is subjective to gravitational conditions.

Q47. What is the basic definition of force in the context of motion?

Answer: Force is generally defined as a push or a pull applied to an object which causes the object to move, stop, or change direction. In the context of motion, force is crucial as it influences the movement of objects. For instance, when riding a bicycle, pushing on the pedals applies force that propels the bicycle forward. Similarly, the wind against a cyclist exerts a counter force, requiring more effort to maintain speed.
Therefore, force is a fundamental component in understanding how objects interact and move in
response to pushes and pulls.

Q48. Describe a real-life application of Archimedes' Principle.

Answer: Ships and submarines apply Archimedes' Principle to control buoyancy. A ship floats because it displaces a volume of water whose weight is equal to the weight of the ship, creating an upward buoyant force that balances its weight. Submarines can submerge or surface by adjusting their buoyancy: they take in water to increase weight and sink, or pump out water to decrease weight and rise, all while obeying Archimedes’ Principle. This principle ensures safe navigation and stability of vessels in water.

Q49. Why is it important to use exact scientific terms and units in science, despite casual use in everyday language?

Answer: Using the correct scientific terms and units is crucial for clarity, accuracy, and consistency in communication and experiments. For example, while everyday language might refer to a 'weight' of 10 kg, scientifically, weight is a force measured in newtons, not an amount of matter. Misusing terms can lead to misunderstandings, inaccurate calculations, and flawed conclusions, especially in scientific research, engineering, and technology, where precision is essential. Correct usage ensures that results are universally understood and reproducible.

Q50. If a ball is thrown upwards, it slows down, stops momentarily, and then falls back to the ground. Name the forces acting on the ball and specify their directions.
i. During its upward motion
ii. During its downward motion
iii. At its topmost position

Answer: i. During its upward motion: Gravitational force pulls the ball downward, slowing it down, while the initial throwing force acts upward but weakens.
ii. During its downward motion: Only gravitational force pulls the ball downward, making it speed up.
iii. At its topmost position: Gravitational force pulls downward; the ball stops momentarily before falling, with zero speed at that instant.

Q51. How can the mass of an object be indirectly measured using a spring balance or a beam balance?

Answer: The mass of an object can be indirectly measured by first finding its weight using a spring balance. Since weight is related to mass through gravitational force, determining the weight allows the calculation of mass. Alternatively, a beam balance can compare the weight of the unknown mass object to a known mass object, inferring the mass of the unknown object.

Q52. What is the gravitational weight of a 1kg object on the Moon compared to Earth, and why does it differ?

Answer: A 1 kg object weighs 10 N on Earth and only 1.6 N on the Moon. This difference occurs because weight is the force of gravity acting on an object, and the Moon’s gravitational pull is much weaker than Earth’s. While the object’s mass remains constant at 1 kg, its weight changes depending on the strength of the gravitational field it is in. Therefore, objects weigh less on the Moon even though their mass does not change.

Q53. Analyze the role of friction in everyday activities by giving examples of both its beneficial and disadvantageous effects.

Answer: Friction plays a critical role in daily activities. On the beneficial side, it allows us to walk without slipping, enables vehicles to grip the road and stop, and allows objects to be placed on surfaces without sliding off. However, friction can also be disadvantageous; it causes wear and tear on moving parts, reduces efficiency by generating heat (as seen in machinery and engines), and necessitates more energy to maintain motion. The advantages and disadvantages depend on the context of the interaction.

Q54. What does "forces work in pairs" mean?

Answer: When you push an object, it exerts an equal and opposite force on you. The interaction ends when contact ends. Opening a door involves a 'pull' or 'push' depending on the direction. Lifting a book is a 'pull', whereas closing a drawer requires a 'push'. Some examples are pushing a shopping cart (push), tugging a rope in tug-of-war (pull), and playing with a computer mouse (push/pull). Pulling up your socks is a 'pull', pushing a button is a 'push', and pulling a kite string is a 'pull'. Examples include: sliding a window (push or pull), pushing a paper pin to a corkboard (push), and dragging a suitcase (pull).

Q55. State whether the given statement is True or False:
(a) When your hand pushes a table, only the table experiences a force.
(b) Due to friction, the speed of the ball rolling on a flat ground increases.
(c) Magnitude is the strength of a force.
(d) A force is always required to change the speed of motion of an object.

Answer: State whether the given statement is True or False:
(a) (b) False
Explanation: Each interacting object feels a force from the other.
(b) (b) False
Explanation: Friction slows down or stops moving objects.
(c) (a) True
Explanation: The statement "Magnitude is the strength of a force" is actually True, not False. The magnitude of a force refers to how strong or large the force is. For example, a force of 20 N has a greater magnitude than a force of 10 N.
(d) (a) True
Explanation: Force changes speed, direction, or shape.

Q56. How does the concept of force relate to everyday activities, such as cycling?

Answer: The concept of force is intrinsically related to everyday activities such as cycling. When cycling, the rider uses their legs to exert force on the pedals, creating motion that propels the bicycle forward. At the same time, cyclists encounter external forces such as wind resistance, friction between tires and road, and gravitational pull. For example, when cycling uphill, greater force is needed to overcome gravity and friction, whereas descending a slope, gravity assists in moving the bicycle downhill, reducing the pedaling effort required. Cyclists also adjust their posture to minimize air resistance, showing how force and motion are interconnected. Thus, the interaction between applied and external forces determines the ease, speed, and energy expenditure during cycling, illustrating the practical application of force in daily life.

Q57. Describe a real-life situation where Archimedes' Principle might be applied, explaining how it relates to floating or sinking.

Answer: A real-life situation where Archimedes' Principle applies is in designing ships and submarines. Shipbuilders use this principle to calculate buoyancy, ensuring that the weight of water displaced by a ship is equal to or greater than the ship's weight, allowing it to float safely. Submarines utilize this principle to dive and rise by adjusting water intake to change their overall density relative to ocean water. Additionally, the shape and volume of the vessel are carefully designed to maximize displacement and stability. By calculating buoyancy accurately, engineers ensure that vessels function efficiently, remain stable, and avoid capsizing, demonstrating the application of Archimedes’ Principle in determining stability, flotation, and controlled submersion of vessels in water.

Q58. Explain why hitting a moving ball with a bat is an example of force application, and discuss the outcome of such a force.

Answer: When a bat hits a moving ball, a force is applied in the form of a push. This action exemplifies force application because it externally impacts the ball, changing its motion. The applied force can redirect the ball’s trajectory, increase or decrease its speed, and sometimes slightly deform the ball at the point of contact. The outcome of the force depends on several factors: the angle of impact, the strength of the hit, the direction of the applied force, and the mass of the ball. Additionally, the interaction demonstrates Newton’s laws of motion—the ball accelerates in the direction of the applied force, and an equal and opposite reaction acts on the bat. This example clearly shows how external forces can manipulate an object’s motion and state, making it an ideal real-life illustration of force application.

Q59. Read the following text carefully and answer the questions that follow: When an object is placed in water, it experiences two forces: the downward gravitational force and the upward buoyant force (upthrust). If gravity is greater, the object sinks; if both are equal, it floats. Archimedes’ Principle states that an immersed object experiences an upward force equal to the weight of liquid displaced. The buoyant force also depends on liquid density. Interestingly, light porous rocks like pumice can float because they are less dense than water.
Questions:
a. What is the force applied by a liquid in the upward direction called? (1)
b. State Archimedes’ Principle in simple terms. (1)
c. Why does a plastic bottle float in water but a stone sinks? (2) OR Why can pumice rock float on water while most rocks sink? (2)

Answer: a. The force applied by a liquid in the upward direction is called buoyant force.
b. Archimedes’ Principle states that when an object is fully or partially immersed in a liquid, it experiences an upward force equal to the weight of the liquid displaced. This principle helps explain why objects float or sink.
c. A plastic bottle is lighter and displaces enough water to balance its weight, so the buoyant force equals the gravitational force, making it float. A stone, however, is denser and heavier. The water displaced is not enough to balance its weight, so the downward gravitational pull is stronger, causing it to sink. OR Pumice forms during volcanic eruptions when lava cools quickly with trapped gases, creating air-filled pores. These pores reduce its density, making it less dense than water. Since buoyant force can balance its weight, pumice floats. In contrast, most rocks are much denser than water, so their gravitational force is greater than buoyant force, causing them to sink.

Q60. Read the following text carefully and answer the questions that follow: Sonali and Ragini went cycling during their summer vacation. While riding against the wind, they noticed it was harder to pedal. On rough paths, cycling was difficult, but smoother paths made it easier. When returning downhill, their bicycles moved quickly even without pedalling, making them realise that something was pulling them downward. This experience introduces the idea of force, which in science is described as a push or pull acting on an object.
Questions:
a. What is an unbalanced force? (1)
b. Why did Sonali and Ragini find it difficult to cycle against the wind? (1)
c. How does the experience of riding downhill without pedalling explain the concept of force? (2) OR Compare the effect of rough and smooth roads on cycling. What does this tell us about forces? (2)

Answer: a. When forces acting on an object are unequal, causing a change in its motion, they are unbalanced forces.
b. Cycling against the wind was difficult because the wind exerted a force in the opposite direction of their motion. This opposing force resisted their pedalling, requiring them to apply more effort to move forward.
c. When Sonali and Ragini cycled downhill, their bicycles moved faster even without pedalling. This happened because the force of gravity pulled them downward along the slope. This shows that force can act on objects without physical contact, changing their motion by increasing speed in the direction of the pull. OR On rough roads, frictional force was higher, making it harder for Sonali and Ragini to pedal. On smooth paths, friction was lower, so cycling became easier. This shows that friction, a type of force, resists motion. The smoother the surface, the lesser the opposing force, making movement easier.

Q61. Read the following text carefully and answer the questions that follow: Forces are of two types-contact and non-contact. Contact forces, like muscular force and friction, act only when objects touch each other. Friction always opposes motion and depends on the surface type. Non-contact forces act without contact, such as magnetic force (attraction/repulsion of magnets), electrostatic force (forces between charged bodies), and gravitational force (Earth pulling objects downward). While magnetic and electrostatic forces may attract or repel, gravitational force is always attractive.
Questions:
a. Which force is always attractive in nature? (1)
b. Differentiate between contact and non-contact forces with examples. (1)
c. How does friction act as a contact force? Explain with examples. (2) OR Compare gravitational, magnetic, and electrostatic forces in terms of nature and effects. (2)

Answer: a. Gravitational force is always attractive.
b. Contact forces require physical touch, like muscular force (pushing a cart) or friction (slowing a bicycle). Non-contact forces act from a distance, like magnetic force, electrostatic force, and gravitational force. Both types change motion, speed, or shape of objects.
c. Friction is a contact force that opposes motion between two surfaces in contact. It arises due to surface irregularities. For example, a rolling ball slows down due to ground friction, and a bicycle stops sooner on rough roads. Friction is useful for walking, writing, or holding objects but can also cause wear and energy loss. OR Gravitational force is always attractive and pulls objects toward Earth. Magnetic force can be attractive or repulsive depending on pole interactions. Electrostatic force also shows both attraction and repulsion between charged bodies. While gravity acts universally on all masses, magnetic and electrostatic forces depend on material type and electric charge. All three act without physical contact.

Q62. Read the following text carefully and answer the questions that follow: Weight is the force with which the Earth pulls an object towards itself, measured in newton (N). It varies with gravitational force, while mass remains constant everywhere. A spring balance is commonly used to measure weight, where stretching of the spring shows readings. Objects of the same mass weigh differently on different planets. In daily life, people often confuse mass and weight, though scientifically mass is the matter in an object and weight is gravitational pull.
Questions:
a. Name the instrument commonly used to measure the weight of an object. (1)
b. Differentiate between mass and weight. (1)
c. How does a spring balance measure weight? Explain with an example. (2) OR Why does the same object have different weights on different planets? (2)

Answer: a. Spring balance is commonly used to measure the weight of an object.
b. Mass is the amount of matter in an object, measured in grams (g) or kilograms (kg), and remains constant everywhere. Weight is the gravitational force acting on an object, measured in newtons (N), and can vary from place to place or on different planets.
c. A spring balance has a spring fixed at one end and a hook at the other. When an object is hung, Earth’s pull (weight) stretches the spring. The amount of stretch shows the weight on a calibrated scale. For example, a pencil box hung on a spring balance may stretch it to indicate 2 N, which represents its weight. OR Weight depends on the gravitational pull of the planet. Since different planets exert different gravitational forces, the same mass shows different weights. For example, a 1 kg object weighs 10 N on Earth, 1.6 N on the Moon, and 25.4 N on Jupiter. This proves that mass stays constant, but weight changes with location and planetary gravity.

Q63. Fill in the blanks:
(a) A force is a ________ or ________.
(b) The body at rest is called ________ body.
(c) ________ force is the force resulting due to the action of muscles.
(d) Force has ________ as well as direction.
(e) The upward force exerted by a liquid on an immersed object is called ________ force. (f) Gravity is always ________ (g) If an object's speed or direction changes, a ________ has acted. (h) Force exerted by magnet is called ________ force.
(i) Force is ________ to pressure. (j) The SI unit of force is ________.

Answer: Fill in the blanks:
(a) push, pull
(b) Stationary
(c) Muscular
(d) Magnitude
(e) buoyant (or upthrust) (f) attractive (g) force (h) Magnetic
(i) Directly Proportional (j) newton