Weight and mass of an object are defined with Newton's laws of motion. Which among the following is true?
- (a)Weight is a constant of proportionality.
- (b)Mass is a constant of proportionality.
- (c)Mass is not a constant of proportionality.
- (d)Weight is a universal constant.
Correct — B, mass is a constant of proportionality. Newton's second law writes force as F = m a, so mass m is the fixed factor linking the force applied to the acceleration produced; the same body needs a force proportional to its mass to gain a given acceleration. Weight, by contrast, is the pull of gravity, W = m g, which changes from place to place as g changes, so weight is neither a constant of proportionality nor universal.
- (a)Weight is a constant of proportionality. — Weight is a force, W = m g, that varies with the local value of g; a body weighs about one-sixth as much on the Moon, so weight cannot be the fixed constant in F = m a.
- (c)Mass is not a constant of proportionality. — This denies the very role mass plays; mass is exactly the constant relating force and acceleration in F = m a, so the statement is false.
- (d)Weight is a universal constant. — Weight depends on gravity and location, so it is not universal; only quantities such as the gravitational constant G are truly universal.
Newton's second law is F = m a, in which mass is the constant of proportionality between the force on a body and the acceleration it produces. Mass is the amount of matter in a body and is the same everywhere, whereas weight is the gravitational force on that body and changes with the local acceleration due to gravity.
The distinction turns on the word constant. Mass stays the same everywhere and is the multiplier in F = m a, while weight is a force that shifts with gravity. Spotting that a constant of proportionality must be the unchanging quantity points straight to mass.
- Newton's second law is F = m a, with mass as the constant of proportionality.
- Mass is the amount of matter in a body and stays the same at every location.
- Weight is the gravitational force on a body, W = m g, and changes as g changes.
- Mass is measured in kilograms, while weight is a force measured in newtons.
In F = m a the mass is the constant of proportionality, while weight (m g) varies with gravity.
- Treating weight as a fixed property of a body when it changes with location.
- Confusing mass, measured in kilograms, with weight, measured in newtons.
Asked to pick the true statement about mass and weight under Newton's laws; mass is the constant of proportionality in F = m a.
No directly related past PYQ was found.
- practice — not a real PYQ
In the equation F = m a, the quantity m represents the
- (a)applied force
- (b)mass, the constant of proportionality
- (c)acceleration
- (d)weight
Answer(b) mass, the constant of proportionality — it links force and acceleration.
- practice — not a real PYQ
The weight of a body on the Moon compared with its weight on the Earth is
- (a)the same
- (b)about one-sixth
- (c)six times
- (d)zero
Answer(b) about one-sixth — the Moon's g is roughly a sixth of the Earth's.