📘 Welcome
Hi User, you have selected Read Mode.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
Q1. The weight of an object on the moon is approximately
The acceleration due to gravity on the Moon is about 1.6 m/s², which is approximately one-sixth of the Earth’s gravity (9.8 m/s²). Since weight W = mg, and mass is constant, the weight on the Moon becomes W_moon = m × (g/6) = W_earth/6. So the weight of an object on the Moon is roughly one-sixth of its weight on Earth. This is why astronauts can jump higher and carry heavy equipment easily on the lunar surface. However, the mass of the object remains exactly the same on the Moon as on Earth.
Q2. The relation between earth weight and moon weight is
Since the weight on the Moon is about one-sixth of the weight on Earth, we can write Wm = We/6. Rearranging this gives We = 6Wm. This means the Earth’s weight is six times the Moon’s weight for the same object. This relationship is important for understanding how gravity affects weight on different celestial bodies.
Q3. At a given place, the value of g is
At a given location (fixed latitude and altitude), the acceleration due to gravity g is constant. It does not change for different objects at that place. All objects, regardless of their mass, experience the same value of g at that location. This constancy is why all objects fall with the same acceleration (ignoring air resistance). For example, at sea level at the equator, g is about 9.78 m/s², while at the poles it is about 9.83 m/s². Once you fix the location, g has a specific constant value.
Q4. Weight is a
Weight is a force, and all forces are vector quantities. This means that weight has both magnitude and direction. The magnitude is given by W = mg, and the direction is always towards the centre of the Earth (vertically downward). For example, if you say “an object has a weight of 50 N,” you are only giving the magnitude. To fully describe the weight, you must also specify that it acts downward. This distinguishes weight from mass, which is a scalar quantity (only magnitude, no direction).
Q5. The mass of the earth is denoted by
In physics, the mass of a large body like the Earth is usually denoted by a capital letter M. The mass of a smaller object is denoted by a lowercase m. This convention helps distinguish between the two masses in equations. For example, in the gravitational force formula F = GMm/d², M is the mass of the Earth (or larger body) and m is the mass of the smaller object. The radius of the Earth is usually denoted by R.
Q6. Weight is zero when
Weight is defined as W = mg. For weight to be zero, either the mass m must be zero (which is impossible for any real object) or the acceleration due to gravity g must be zero. If g becomes zero, then W = m × 0 = 0. This would happen in deep space far from any massive object where gravity is negligible, or at the centre of the Earth where gravity cancels out. So weight is zero when there is no gravity acting on the object.
Q7. On the moon, an object’s weight
The weight of an object on the Moon decreases compared to its weight on Earth. This is because the Moon has less mass than the Earth and therefore exerts less gravitational force. The value of g on the Moon is about one-sixth of that on Earth, so the weight is also one-sixth. However, the mass of the object does not change—it is the same on both the Earth and the Moon. This decrease in weight is why objects feel lighter on the Moon.
Q8. The radius of the earth is denoted by
In physics, the radius of a planet (including Earth) is commonly denoted by the capital letter R. In the formula for gravitational force, F = GMm/d², the distance d is measured from the centre of the Earth. For an object on the Earth’s surface, this distance d equals the radius of the Earth, which is denoted by R. So for surface calculations, we can write F = GMm/R². Sometimes the radius is also denoted by r, but in most textbooks, R is used for Earth’s radius.
Q9. The radius of the moon is denoted by
The radius of the Moon is usually denoted by Rm (with a subscript ‘m’ to indicate it is the Moon’s radius). This helps distinguish it from the radius of the Earth (R) and other distances. In equations involving the Moon, using Rm avoids confusion. The radius of the Moon is approximately 1.74 × 10⁶ m. This notation is common in physics when dealing with multiple celestial bodies.
Q10. Weight is measured using
A spring balance is used to measure weight. It works on the principle that the force of gravity (weight) stretches a spring, and the amount of stretch is proportional to the weight. The reading on a spring balance will change depending on the location because weight depends on g. On the Moon, the same object would show a lower reading. A beam balance, on the other hand, is used to measure mass by comparing the object with standard masses. A measuring scale measures length, and a stopwatch measures time.
Q11. Mass is independent of
Mass is a fundamental property of matter and is independent of gravity. It is the amount of matter in an object. Whether the object is on Earth, on the Moon, or in deep space, its mass remains the same. Mass does not depend on the gravitational field. However, weight depends on gravity. Mass is also independent of size, shape, and colour—it only depends on the amount of matter. This is why we say mass is an intrinsic property.
Q12. The weight of an object on the moon is denoted by
The weight of an object on the Moon is denoted by Wm, where the subscript ‘m’ indicates the Moon. Similarly, We is used for weight on Earth. This notation helps us distinguish between weights on different celestial bodies in equations. For example, we can write Wm = (1/6)We to show the relationship between weight on the Moon and weight on Earth.
Q13. The gravitational pull on the moon is weaker because
The Moon has a weaker gravitational pull than the Earth because it has much less mass. The gravitational force depends on mass, and the Moon’s mass is only about 1/81 of Earth’s mass. Even though the Moon is also smaller in radius, the dominant factor for the weaker gravity is its smaller mass. This is why g on the Moon is about 1/6 of g on Earth. The presence or absence of water, air, or rotation does not significantly affect the gravitational pull.
Q14. Weight of an object is denoted by
The weight of an object is represented by the symbol W. This is a standard convention in physics. Mass is represented by m, acceleration due to gravity by g, and force is often represented by F. Weight is a specific type of force (the force of gravity), so it can also be denoted by F. But in most textbooks, W is used specifically for weight. The formula for weight is W = mg.
Q15. The mass of the moon is approximately
The mass of the Moon is approximately 7.36 × 10²² kg. This is about 1/81 of the Earth’s mass (5.98 × 10²⁴ kg). The smaller mass of the Moon is the reason why the acceleration due to gravity on its surface is only about one-sixth of that on Earth. Knowing the Moon’s mass is important for calculating the gravitational force between the Earth and the Moon, which affects tides and the Moon’s orbit.
Q16. The mass of the moon is
The Moon has much less mass than the Earth. The Earth’s mass is about 5.98 × 10²⁴ kg, while the Moon’s mass is about 7.36 × 10²² kg. So the Moon’s mass is about 1/81 of Earth’s mass. This is why the gravitational force on the Moon is weaker. The smaller mass means that objects weigh less there.
Q17. If an object weighs 60 N on earth, its weight on the moon will be
Since the weight on the Moon is one-sixth of the weight on Earth, we can calculate Wm = We/6 = 60/6 = 10 N. This means an object that weighs 60 newtons on Earth would weigh only 10 newtons on the Moon. This calculation is based on the fact that g_moon = g_earth/6. The mass of the object remains the same; only the weight changes because the gravitational field is weaker.
Q18. Weight has
Weight is a vector quantity because it has both magnitude and direction. The magnitude is the value of the weight (e.g., 60 N), and the direction is always towards the centre of the Earth (vertically downward). This is true for all vector quantities—they require both a numerical value and a direction to be fully described. When we say “an object has a weight of 60 N,” we are giving the magnitude. When we say “it acts downward,” we are giving the direction.
Q19. The ratio of earth’s weight to moon’s weight is
Since the weight on the Moon is one-sixth of the weight on Earth, the ratio of Earth weight to Moon weight is We : Wm = We : (We/6) = 6 : 1. This means that an object weighs six times more on Earth than it does on the Moon. This ratio is constant for all objects because it depends only on the difference in gravitational acceleration between the two bodies.
Q20. The SI unit of force and weight is
The SI unit of both force and weight is the newton (N). Weight is a force, so it is measured in newtons. One newton is defined as the force required to give a mass of 1 kilogram an acceleration of 1 m/s². This is why weight W = mg is measured in newtons, since mass is in kilograms and g is in m/s². Kilogram is the unit of mass, meter is the unit of length, and second is the unit of time.
Q21. The moon exerts ______ gravitational force than the earth
The Moon exerts a lesser gravitational force than the Earth because it has much less mass. The gravitational force exerted by a body is directly proportional to its mass. Since the Moon’s mass is about 1/81 of Earth’s mass, its gravitational force is also much weaker. This is why g on the Moon is only about 1.6 m/s² compared to 9.8 m/s² on Earth.
Q22. Mass is measured in
The SI unit of mass is the kilogram (kg). Mass is a fundamental quantity that measures the amount of matter in an object. Unlike weight, which is measured in newtons, mass is a scalar quantity and does not depend on gravity. The kilogram is one of the seven base units of the International System of Units. Other common units of mass include gram (g) and tonne (t).
Q23. The mass of the moon is denoted by
The mass of the Moon is usually denoted by Mm, where the subscript ‘m’ indicates the Moon. This distinguishes it from the mass of the Earth (M) and the mass of smaller objects (m). Using subscripts helps avoid confusion in equations that involve multiple masses, such as those calculating gravitational forces between the Earth, Moon, and other objects. The mass of the Moon is approximately 7.36 × 10²² kg.
Q24. The radius of the earth is approximately
The radius of the Earth is approximately 6.37 × 10⁶ metres (or 6370 kilometres). This is the average radius because the Earth is not a perfect sphere. The radius is needed for many calculations involving gravity, such as finding the value of g, calculating the mass of the Earth, and determining satellite orbits. For most school-level problems, 6.4 × 10⁶ m is used as an approximation.
Q25. At a given place, weight is directly proportional to
At a given place, the acceleration due to gravity g is constant. So weight W = mg is directly proportional to mass. This means if mass doubles, weight doubles; if mass becomes half, weight becomes half. This direct proportionality is why we often use weight as an indicator of mass (though they are different physical quantities). Weight does not depend on density, volume, or area at a given place.
Q26. The force of attraction of the earth on an object is called its
The force of attraction exerted by the Earth on any object is called its weight. This force is due to gravity. The weight is given by W = mg, where m is the mass of the object and g is the acceleration due to gravity. Mass is the amount of matter, density is mass per unit volume, and inertia is the resistance to change in motion. So weight is the correct term for the Earth’s gravitational pull on an object.
Q27. The formula for weight of an object on the moon is
The weight of an object on the Moon is the gravitational force exerted by the Moon on the object. Using Newton’s law of gravitation, this is Wm = G × Mm × m / Rm², where Mm is the mass of the Moon, m is the mass of the object, and Rm is the radius of the Moon. This is the most fundamental formula for weight on the Moon. It can also be written as Wm = m × gm, where gm is the acceleration due to gravity on the Moon (gm = GMm/Rm²).
Q28. Weight is a ______ quantity
Weight is a vector quantity. It has both magnitude (given by mg) and direction (always towards the centre of the Earth). In physics, any quantity that has both magnitude and direction is called a vector. Examples of vectors include force, velocity, and displacement. Weight is a specific type of force, so it shares the vector nature of all forces.
Q29. The universal gravitational constant is denoted by
The universal gravitational constant is denoted by the capital letter G. Its value is 6.67 × 10⁻¹¹ N·m²/kg². This constant appears in Newton’s law of gravitation: F = GMm/d². It is important to distinguish G from g: G is a constant that has the same value everywhere in the universe, while g is the acceleration due to gravity, which varies from place to place. G was first measured by Henry Cavendish.
Q30. The SI unit of weight is
The SI unit of weight is the newton (N). Since weight is a force, it has the same unit as force. One newton is equal to 1 kg·m/s². While mass is measured in kilograms, weight (being a force) is always measured in newtons. This distinction is important in physics. For example, an object with a mass of 10 kg has a weight of about 98 N on Earth (10 × 9.8 = 98 N).
Q31. At a given place, weight can be used as a measure of
At a given place, g is constant. So weight W = mg is directly proportional to mass. This means that if you know the weight of an object at a specific location, you can determine its mass because W/g = m (since g is constant). This is why spring balances, which measure weight, are often calibrated to show mass in kilograms. However, this would not work on the Moon because g is different. Mass is the fundamental quantity, and weight is used as an indirect measure of mass when g is known and constant.
Q32. Weight is a force acting
Weight is the force of gravity acting on an object, and it always acts vertically downward, towards the centre of the Earth. The term “vertical” means along the line from the Earth’s centre to the object. This is the same as the direction of a plumb line (a weight hanging from a string). Weight does not act horizontally or upward. The downward direction of weight is what makes objects fall to the ground.
Q33. Weight depends on
Weight depends on two factors: the mass of the object (m) and the acceleration due to gravity (g) at that location. The formula W = mg shows this clearly. If either mass or g changes, the weight changes. Weight does not depend on volume, density, speed, time, shape, or size. For example, a person has a mass of 60 kg. On Earth (g = 9.8 m/s²), their weight is 588 N. On the Moon (g = 1.6 m/s²), their weight is only 96 N, even though their mass is still 60 kg.
Q34. The formula for weight of an object is
The formula for the weight of an object is W = mg, where W is weight, m is mass, and g is the acceleration due to gravity. Weight is the force of gravity on an object, and it is calculated by multiplying the mass by the gravitational acceleration. This formula comes from Newton’s second law, F = ma, where the force F is the weight, and the acceleration a is g. This is one of the most important formulas in physics.
Q35. On the moon, an object’s mass
Mass is an intrinsic property of matter that does not change with location. Whether an object is on Earth, on the Moon, or in deep space, its mass remains exactly the same. The Moon has weaker gravity, which reduces the object’s weight, but the amount of matter in the object does not change. For example, a person with a mass of 60 kg on Earth has a mass of 60 kg on the Moon as well. Only their weight changes from about 588 N to about 96 N.
Q36. The relation between weight and mass at a given place is
At a given place (where g is constant), weight W = mg is directly proportional to mass m. This means if the mass increases, the weight increases proportionally. The symbol ∝ means “is proportional to.” For example, if you double the mass, the weight doubles. This direct proportionality is why we can use weight as a measure of mass at a fixed location.
Q37. Weight always acts towards
Weight always acts towards the centre of the Earth. This is because the gravitational force of the Earth pulls everything towards its centre. The direction of weight is along the line connecting the object to the Earth’s centre. This is what we call “downward.” This direction is the same for all objects, regardless of where they are on the Earth’s surface.
Q38. Weight changes when
Weight changes when the location changes because g varies from place to place. On Earth, g is slightly different at different latitudes and altitudes. On the Moon, g is much smaller. Since W = mg, any change in g results in a change in weight. The mass remains the same, but the weight changes. Shape, colour, and volume do not affect weight. For example, an object weighs less at the top of a high mountain than at sea level, and much less on the Moon.
Q39. When the expressions for Wm and We are divided, the ratio obtained is
Since the weight on the Moon is one-sixth of the weight on Earth, the ratio Wm/We = 1/6. This ratio is constant for all objects because it depends only on the ratio of the gravitational accelerations on the two bodies. This is a useful relationship for converting weights between Earth and the Moon.
Q40. The mass of an object remains
Mass is a fundamental property of matter and is the same everywhere in the universe. It does not depend on location, gravity, or any other external factor. The mass of an object is a measure of the amount of matter in it, and this amount is fixed regardless of where the object is. Whether on Earth, the Moon, Mars, or in deep space, the mass remains unchanged. Only the weight changes with location.
Q41. The weight of an object on the earth is denoted by
The weight of an object on Earth is denoted by We, where the subscript ‘e’ indicates Earth. This helps distinguish it from weight on the Moon (Wm) or other celestial bodies. In many problems, We is used to represent the weight on Earth, and the relationship We = 6Wm is used to solve problems involving weight on the Moon.
Q42. The weight of an object depends on
Weight depends on the location because the acceleration due to gravity g varies from place to place. The formula W = mg shows that weight depends on g. On Earth, g varies slightly with altitude and latitude. On the Moon, g is much smaller. Volume, shape, and colour do not affect weight. Only mass and the value of g at that location determine the weight.
Q43. Weight is proportional to
Weight W = mg is directly proportional to mass m at a given location where g is constant. This means that an object with greater mass has greater weight. Weight does not depend on area, density, or volume directly. For example, a larger volume object may have more mass, but it is the mass (not the volume) that determines the weight.
Q44. The direction of weight is always
Weight is a force that always acts vertically downward, towards the centre of the Earth. This is because gravity pulls objects towards the Earth’s centre. This direction is constant and is the same for all objects, regardless of their shape, size, or mass. The vertical downward direction is what we commonly refer to as “down.”
Q45. The formula for weight of an object on the earth is
The weight of an object on the Earth’s surface is the gravitational force between the Earth and the object. Using Newton’s law of gravitation, this is We = G × M × m / R², where G is the universal gravitational constant, M is the mass of the Earth, m is the mass of the object, and R is the radius of the Earth. This can also be written as We = m × g, where g = GM/R². Both formulas are correct and equivalent.
Q46. The weight of an object on the moon is the force with which the moon
Weight is always the attractive gravitational force exerted by a celestial body on an object. On the Moon, the weight of an object is the force with which the Moon attracts the object towards its centre. Just like on Earth, weight on the Moon is a downward force directed towards the centre of the Moon.
Q47. The radius of the moon is approximately
The radius of the Moon is approximately 1.74 × 10⁶ metres (or 1740 kilometres). This is about one-quarter of the Earth’s radius (which is 6.37 × 10⁶ m). The Moon’s smaller radius, along with its smaller mass, contributes to the weaker gravitational acceleration on its surface.
Q48. Weight depends on location because g
Weight depends on location because the acceleration due to gravity g depends on location. The value of g varies with altitude, latitude, and the mass of the celestial body. For example, g is smaller at higher altitudes, smaller at the equator than at the poles, and much smaller on the Moon than on Earth. Since W = mg, any change in g causes a change in weight.
Q49. The mass of the earth is approximately
The mass of the Earth is approximately 5.98 × 10²⁴ kg (about 6 × 10²⁴ kg for most calculations). This large mass is what gives the Earth its strong gravitational pull. The mass was calculated using Newton’s law of gravitation after Cavendish determined the value of G. Knowing the Earth’s mass is essential for understanding gravity, satellite motion, and many other phenomena.
Q50. The reduction in weight on the moon is due to
The reduction in weight on the Moon is mainly due to the Moon’s smaller mass. The Moon’s mass is only about 1/81 of the Earth’s mass. This smaller mass results in a much weaker gravitational field on its surface. As a result, the acceleration due to gravity on the Moon (g_moon = 1.6 m/s²) is only about one-sixth of that on Earth. While the smaller radius also plays a minor role, the dominant factor for the weaker gravity is the Moon’s smaller mass.