Speed and velocity are both terms used to describe the motion of an object, but they have different meanings.
Speed refers to how fast an object is moving and is a scalar quantity. It is calculated by dividing the distance traveled by the time taken. Speed does not consider the direction of motion, only the magnitude. For example, if a car travels 100 kilometers in 2 hours, its speed would be 50 kilometers per hour.
Velocity, on the other hand, is a vector quantity that takes into account both the speed and the direction of motion. It is the rate at which an object changes its position. Velocity is calculated by dividing the displacement (change in position) by the time taken. Displacement is a vector that points from the initial position to the final position of an object. For example, if a car travels 100 kilometers north in 2 hours, its velocity would be 50 kilometers per hour north.
Acceleration is the rate at which an object's velocity changes over time. It is also a vector quantity and is defined as the change in velocity divided by the time taken. Acceleration can result from a change in speed, a change in direction, or both. If an object speeds up, slows down, or changes its direction of motion, it is experiencing acceleration. For example, when a car increases its speed from 0 to 100 kilometers per hour in 10 seconds, it is undergoing acceleration.
In summary, speed is a scalar quantity that describes how fast an object is moving, while velocity is a vector quantity that includes both the speed and direction of motion. Acceleration is the rate of change of velocity and can occur due to changes in speed, direction, or both.