Physics Formulas

Velocity Formula

Today we are going to discuss velocity and then the velocity formula. First of all, we are going to define what velocity is.

Definition of velocity


Velocity is similar to speed but it has direction. Let's recap what a speed is. Speed is the rate at which something is moving.

For example, a swimmer may swim at the speed of 1 meter per second but he or she swims at the velocity of 1 meter per second east. By specifying that he or she swims in the eastwardly direction, you are defining the velocity he or she swims at. So, when you measure velocity, remember to report both speed and direction, the two components of velocity.

velocity expression

Velocity formula

Math formula for speed

Since velocity has direction, it is referred to in Physics as a vector quantity. A vector quantity means it is directional as opposed to a scalar quantity which is what speed is. The formula of velocity used in physics is the same as the formula used for measuring average speed per direction. Let's examine how the velocity formula works.

 velocity formula

In the diagram above, the three velocities represented are A, B, and C. A is the speed measured in the Eastward direction, B is the speed measured in the south-eastern direction and C is the speed measured in the Northeast direction. For example, velocity A is 10 m/s east, V is 20 m/s southeast and C is 15 m/s northeast.

That's it. The velocity is measured in meter per second, the same SI unit as speed. Just remember to specify direction when reporting the velocity.