What is the difference between speed and velocity?

Speed

The speed is essentially the physical quantity that tells us how fast or slow an object moves. The speed of an object is defined as “the rate of change of its distance with respect to time”. Mathematically,

speed = distance/time.

It is a scalar quantity. It requires the only magnitude to define it.

Since speed = distance/time, there can be numerous units. For example, km/h, km/s, m/s, m/h, etc. These all are valid in only some situations. For example, speed of light, since very fast, is represented in km/s and speed of a snail, since very slow, is represented in m/h. But the SI unit of speed is given by m/s.

For example, if a car takes 20 seconds to travel 200 meters then the speed of the car is 200/20 = 10 m/s

Velocity

Velocity is defined as the rate of change of displacement with respect to time. It is the speed at which an object moves in a particular direction. It is a vector quantity. It needs both magnitude and direction to represent it. The SI unit of velocity is m/s.

Mathematically, velocity is given as

V = distance/time

Where, v = velocity, d = distance, t = time.