**Motion** is the change of position of an object with respect to time. For example, a car moving on a road, a bird flying in the sky, or a ball rolling down a hill are all examples of motion. Motion can be described by using different terms, such as distance, displacement, speed, velocity, and acceleration. Motion can also be classified into different types, such as linear motion, rotatory motion, and oscillatory motion. Linear motion is when an object moves in a straight line. Rotatory motion is when an object spins around an axis. Oscillatory motion is when an object moves back and forth in a regular pattern.

The difference between speed and velocity is that speed is the rate of change of distance, while velocity is the rate of change of displacement. Speed only tells you how fast an object is moving, while velocity also tells you the direction of its motion. Speed is a scalar quantity, which means it only has magnitude (size or amount). Velocity is a vector quantity, which means it has both magnitude and direction. For example, if a car is moving at 60 km/h on a straight road, its speed and velocity are both 60 km/h. But if the car turns left or right, its speed remains the same, but its velocity changes because its direction changes.

To calculate speed, you need to divide the distance traveled by the time taken. The formula for speed is:

$speed=distance/ time $

The unit of speed is usually meters per second (m/s) or kilometers per hour (km/h).

To calculate velocity, you need to divide the displacement by the time taken. Displacement is the change in position of an object, which means you need to subtract the initial position from the final position. The formula for velocity is:

$velocity=displacement/time $

The unit of velocity is also meters per second (m/s) or kilometers per hour (km/h), but you also need to specify the direction of the motion.

A** vector quantity** is a physical quantity that has both magnitude and direction. For example, force, displacement, velocity, acceleration, and momentum are all vector quantities. To represent a vector quantity, we usually use an arrow that points in the direction of the vector and has a length proportional to the magnitude of the vector.