The correct option is **C. Displacement**. ### 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 displacement, velocity, and force. 2. **Analyzing the Options**: - **A. Temperature**: This is a scalar quantity. It tells us how hot or cold something is, but it does not have a direction associated with it. For example, saying the temperature is 25 degrees Celsius gives us a magnitude but no direction. - **B. Speed**: This is also a scalar quantity. Speed measures how fast an object is moving, but it does not indicate the direction of that movement. For instance, if a car is traveling at 60 km/h, we know the rate of travel but not where the car is headed. - **C. Displacement**: This is a vector quantity. Displacement measures the change in position of an object and includes both the distance moved and the direction of that movement. For example, if an object moves from point A to point B, the displacement is not just the distance between A and B but also the direction from A to B. If an object moves 5 meters to the east, its displacement is 5 meters east. - **D. Mass**: This is a scalar quantity. Mass measures the amount of matter in an object and does not have a direction. For example, an object with a mass of 10 kg has a magnitude but no 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 tell us where it is moving to or from. - **Mass (D)**: Similar to temperature, mass is a measure of quantity without any directional aspect. ### Formulas and Concepts - **Displacement Formula**: \[ \text{Displacement} = \text{Final Position} - \text{Initial Position} \] This formula shows that displacement is concerned with the change in position, which inherently includes direction. ### Common Pitfalls - Students often confuse speed with velocity. Remember, velocity is the vector counterpart of speed and includes direction. - It’s important to remember that while both displacement and distance measure how far an object has moved, only displacement includes direction, making it a vector. ### Revision Summary - **Scalars** have magnitude only (e.g., temperature, speed, mass). - **Vectors** have both magnitude and direction (e.g., displacement). - Displacement is the only vector quantity among the options provided. - Always differentiate between similar terms: speed (scalar) vs. velocity (vector). By understanding these distinctions, you can better grasp the concepts of vectors and scalars in physics.