**Correct Option: A. Mass is a measure of the amount of matter in an object, while weight is the force exerted on that mass due to gravity.** ### Detailed Explanation: 1. **Understanding Mass:** - Mass is a fundamental property of matter. It quantifies the amount of matter in an object and is usually measured in kilograms (kg). - Mass is an intrinsic property, meaning it does not change regardless of the object's location in the universe. For example, a 10 kg object on Earth has the same mass as a 10 kg object on the Moon or in space. 2. **Understanding Weight:** - Weight, on the other hand, is the force exerted on an object due to gravity. It is calculated using the formula: \[ W = m \cdot g \] where \( W \) is weight, \( m \) is mass, and \( g \) is the acceleration due to gravity (approximately \( 9.81 \, \text{m/s}^2 \) on Earth). - Weight is a force and is measured in newtons (N). For example, an object with a mass of 10 kg on Earth would have a weight of: \[ W = 10 \, \text{kg} \cdot 9.81 \, \text{m/s}^2 = 98.1 \, \text{N} \] 3. **Key Differences:** - The primary difference is that mass is a measure of how much matter is present, while weight is the force that results from the gravitational pull on that mass. This distinction is crucial in physics and helps in understanding various concepts, such as free fall, weightlessness, and the effects of gravity on different celestial bodies. ### Why Other Options Are Incorrect: - **Option B: Mass varies with location, while weight remains constant.** - This statement is incorrect. Mass does not vary with location; it remains constant regardless of where the object is in the universe. Weight, however, does vary depending on the gravitational field strength. For example, an object weighs less on the Moon than on Earth due to the Moon's weaker gravitational pull. - **Option C: Mass can be measured in newtons, while weight is measured in kilograms.** - This statement is also incorrect. Mass is measured in kilograms (kg), while weight is measured in newtons (N). This is a common misconception, but it is essential to remember that mass and weight are different physical quantities with different units. - **Option D: Mass is a vector quantity, while weight is a scalar quantity.** - This statement is misleading. Mass is a scalar quantity, meaning it has magnitude but no direction. Weight, however, is a vector quantity because it has both magnitude and direction (the direction is towards the center of the gravitational body, such as Earth). Therefore, this option is incorrect. ### Summary of Key Points: - **Mass** is the amount of matter in an object and is measured in kilograms (kg); it does not change with location. - **Weight** is the force due to gravity acting on that mass, calculated as \( W = m \cdot g \), and is measured in newtons (N). - Mass is a scalar quantity, while weight is a vector quantity. - Understanding the distinction between mass and weight is crucial for solving problems in physics related to forces, motion, and gravity.