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 distance. - **Vectors**, on the other hand, have both magnitude and direction. Examples include force, velocity, and displacement. 2. **Analyzing Each Option**: - **A. Temperature**: - Temperature is a scalar quantity. It is measured in degrees (Celsius, Fahrenheit, Kelvin) and indicates how hot or cold an object is. It does not have a direction associated with it. - **B. Speed**: - Speed is also a scalar quantity. It measures how fast an object is moving, expressed in units like meters per second (m/s). Like temperature, speed does not indicate direction; it only tells you how much distance is covered over time. - **C. Force**: - Force is a vector quantity. It is defined as an interaction that causes an object to change its velocity (which includes starting, stopping, or changing direction). Force has both magnitude (how strong the force is) and direction (where the force is applied). It is measured in newtons (N). - **D. Distance**: - Distance is a scalar quantity that measures how much ground an object has covered during its motion, regardless of its starting or ending point. It is measured in units like meters (m) and does not have a direction. 3. **Why Other Options Are Incorrect**: - **Temperature (A)**: Lacks direction; it only tells you how hot or cold something is. - **Speed (B)**: Similar to temperature, it only provides information about how fast something is moving, without any directional context. - **Distance (D)**: Measures the total path length traveled, again without any directional information. ### Formulas and Concepts - **Force**: The formula for force is given by Newton's second law of motion: \[ F = m \cdot a \] where \( F \) is the force, \( m \) is the mass of the object, and \( a \) is the acceleration. This formula illustrates that force is dependent on both the mass (a scalar) and the acceleration (which is also a vector). ### Common Pitfalls - Students often confuse scalars and vectors, especially when they are familiar with the terms. Remember that the key difference is the presence of direction in vectors. - It’s important to visualize vectors as arrows where the length represents magnitude and the arrowhead indicates direction. ### Revision Summary - Scalars have only magnitude (e.g., temperature, speed, distance). - 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 in physics for solving problems related to motion and forces.