Physics

What is the difference between a vector and a scalar quantity?

09/12/2017

Vectors are quantities that have a size and a direction.

Examples: Displacement, velocity, acceleration, momentum, force.

Scalars are quantities that have a size but no direction.

Examples: Temperature, cost, speed, length, height, width, age, energy.

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Scalar quantities have only magnitude. Vector quantities have both magnitude and direction. Temperature and volume are scalar because they don't have a particular direction.

Velocity and Force (because acceleration actually has a direction) are vector quantities.

Velocity is the combination of the scalar quantity of speed with a direction for that speed. Speed is always a positive number but velocity can be negative and positive because it has a direction.