Which of the following is a scalar quantity?
Speed
Velocity
Displacement
Acceleration
Speed
Speed is a scalar quantity.
To determine which of the given quantities is a scalar quantity, we need to understand the difference between scalars and vectors.
Scalars are physical quantities that only have magnitude (size or quantity), while vectors have both magnitude and direction. Scalar quantities can be fully described by a single number or value.
Let's go through each option:
1. Speed: Speed is the magnitude of the velocity vector. It represents how fast an object is moving without regard to its direction. Since speed only has magnitude, it is a scalar quantity.
2. Velocity: Velocity is a vector quantity as it includes both magnitude (speed) and direction. It describes the rate at which an object changes its position. So, velocity is a vector quantity.
3. Displacement: Displacement is a vector quantity that measures the change in position of an object. It considers both the magnitude and direction of the change. Therefore, displacement is not a scalar quantity.
4. Acceleration: Acceleration is a vector quantity as it includes both magnitude and direction. It represents the rate at which the velocity of an object changes over time. Hence, acceleration is not a scalar quantity.
In summary, among the given options, only speed is a scalar quantity.