The correct option is **C. Force**. ### Detailed Explanation 1. **Understanding Scalars and Vectors**: - In physics, quantities are classified into two categories: scalars and vectors. - **Scalars** are quantities that have only magnitude (size) and no direction. Examples include temperature, speed, and mass. - **Vectors**, on the other hand, have both magnitude and direction. Examples include force, velocity, and displacement. 2. **Analyzing the Options**: - **A. Temperature**: This is a scalar quantity. It tells us how hot or cold something is but does not have a direction associated with it. For example, saying the temperature is 30 degrees Celsius does not imply any direction. - **B. Speed**: This is also a scalar quantity. Speed indicates how fast an object is moving but does not provide any information about the direction of that movement. For instance, if a car is traveling at 60 km/h, it tells us the rate of travel but not the direction (north, south, etc.). - **C. Force**: This is a vector quantity. Force not only has a magnitude (how strong the force is) but also a direction (where the force is applied). For example, if you push a box with a force of 10 Newtons to the right, both the strength of the push (10 N) and the direction (to the right) are important. The vector nature of force is crucial in understanding how objects move and interact. - **D. Mass**: This is a scalar quantity as well. Mass measures the amount of matter in an object and does not have a direction. For example, an object with a mass of 5 kg is simply stating how much matter is present, without any directional component. 3. **Why Other Options Are Incorrect**: - **Temperature (A)**: Lacks direction; it is purely a measure of thermal energy. - **Speed (B)**: While it indicates how fast something is moving, it does not specify the direction of that movement, making it a scalar. - **Mass (D)**: Similar to temperature, mass is a measure of quantity without any directional aspect. ### Common Pitfalls - Students often confuse speed with velocity. Remember, velocity is a vector because it includes direction (e.g., 60 km/h north), while speed is just the magnitude (60 km/h). - It’s also easy to overlook that while many physical quantities can be expressed in terms of their effects (like force causing acceleration), the fundamental definitions of scalars and vectors are based on their properties of directionality. ### Revision Summary - Scalars have only magnitude (e.g., temperature, speed, mass). - Vectors have both magnitude and direction (e.g., force). - Force is the only vector quantity among the options provided. - Understanding the distinction between scalars and vectors is crucial for solving physics problems effectively.