**Correct Option: B** ### Explanation of the Correct Answer **Mass vs. Weight: Definitions** - **Mass** is a measure of the amount of matter in an object. It is a scalar quantity, which means it has magnitude but no direction. The standard unit of mass in the International System of Units (SI) is the kilogram (kg). - **Weight**, on the other hand, is the force exerted on an object due to gravity. It is a vector quantity, meaning it has both magnitude and direction (the direction is towards the center of the gravitational body, like Earth). The standard unit of weight in the SI system is the newton (N). **Why Option B is Correct** - Option B correctly states that mass is a scalar quantity measuring the amount of matter, while weight is a vector quantity that measures the gravitational force acting on that mass. This distinction is fundamental in physics because it helps us understand how objects behave under the influence of gravity. **Mathematical Relationship** The relationship between mass (m) and weight (W) can be expressed with the formula: \[ W = m \cdot g \] where: - \( W \) is the weight in newtons (N), - \( m \) is the mass in kilograms (kg), - \( g \) is the acceleration due to gravity (approximately \( 9.81 \, \text{m/s}^2 \) on the surface of the Earth). This formula shows that weight depends on both the mass of the object and the gravitational field strength. ### Why the Other Options are Incorrect **Option A:** - "Mass is a measure of the gravitational force acting on an object, while weight is a measure of the object's resistance to motion." - This statement is incorrect because it confuses the definitions of mass and weight. Mass does not measure gravitational force; it measures the amount of matter. Weight is indeed related to gravitational force, but resistance to motion is a concept related to inertia, which is a property of mass, not weight. **Option C:** - "Mass varies depending on the location in the universe, while weight remains constant everywhere." - This statement is also incorrect. Mass is an intrinsic property of an object and does not change regardless of location. Weight, however, can vary depending on the gravitational field strength at a location (e.g., an object weighs less on the Moon than on Earth due to the Moon's weaker gravity). **Option D:** - "Mass can be measured in newtons, while weight is measured in kilograms." - This statement is incorrect because it reverses the units. Mass is measured in kilograms (kg), while weight is measured in newtons (N). This is a fundamental distinction in physics. ### Common Pitfalls - Confusing mass and weight is a common mistake. Remember that mass is a measure of matter, while weight is a force due to gravity. - Forgetting that weight can change with location due to varying gravitational forces can lead to errors in calculations and understanding. - Misunderstanding the units: always remember that mass is in kilograms and weight is in newtons. ### Revision Summary - **Mass** is a scalar quantity representing the amount of matter in an object (measured in kg). - **Weight** is a vector quantity representing the gravitational force on that mass (measured in N). - Weight varies with the strength of the gravitational field, while mass remains constant regardless of location. - The formula \( W = m \cdot g \) connects mass and weight, highlighting their relationship.