To explain velocity to a kid you can explain velocity as the velocity being an object's speed in a specific direction and speed only tells you how fast something is moving like 60 mph.
Velocity includes the speed as well as the direction like 60 mph North that the object is going.
Velocity is a vector quantity, which means that it shows both magnitude and direction.
The direction also matters in velocity and so for example if a car is driving 20 mph in a circle, the speed of the car is constant, but it's velocity is also constantly changing because it's direction is also changing when driving in a circle.
Velocity is the rate that an object changes it's position in a specific direction, combining both speed as well as direction.
And unlike just speed "how fast", velocity is a vector quantity, which means that velocity includes magnitude and direction like for example, 60 km/h North.
Velocity is calculated as displacement divided by time.
Velocity requires both speed (magnitude) and direction.
The difference from speed and velocity is that speed is a scalar like (50 mph) for example and velocity is a vector like (50 mph East).
An object can also have speed but also have 0 velocity.
If the object returns to it's starting point then the displacement is zero.
Velocity is also commonly measured in meters per second or (m/s) in the SI system, or kilometers per hour (km/h), miles per hour or (mph).
Velocity is also used in physics to calculate momentum like for example momentum = mass X velocity and in engineering to determine motion.
When you're driving, your vehicle's speedometer is showing your speed, but your GPS navigation system is showing your velocity by factoring in your direction.
Simply put, velocity is how fast something is moving and the direction it's going, like a car going 60 miles per hour north, while speed is just how fast, like 60 miles per hour.
You can think of velocity as speed with a compass direction (north, south, east, west, or up/down) attached, making it a "direction-aware" measurement of motion.
For example for speed, a skateboarder would be going 5 miles per hour or mph.
And for the velocity of the skateboarder the skateboarder would be going 5 mph down the hill.