Posted by Difference Between Speed and Velocity
Let us understand the difference between speed and velocity in detailed and in the tabular form. Sometimes we find these terms similar but there is a difference between them
| Parameter | Velocity | Speed |
|---|---|---|
| Definition | The rate at which an object changes its position | It is defined as the rate at which an object covers a distance |
| Type of Quantity | Velocity is a vector quantity | Speed is a scalar quantity |
| Unit | It is measured in M/S where M is Meter and S is second | It is measured in M/S where M is Meter and S is second |
| Interrelation | An object may possess different velocities but at the same speed. | Speed may or may not be equal to velocity. |
| Change of direction | The velocity of the object changes with the change in direction, | The average speed will continue to count even if the object changes its direction |
| Magnitude | It can be negative, zero or positive | It can never be negative or zero |
| Formula | Velocity = Displacement / Time | Speed = Distance / Time |
| Types | Constant velocity, changing velocity, instant velocity, terminal velocity | Uniform speed, Non-uniform speed, |
What is Speed?
Speed is defined as the distance covered by any object per unit time according to Galileo. Let us understand it through example, a man moving by bike would cover a large distance as compared to a man who is simply walking in the same time period. The SI unit of speed is
Speed = Ditance / Time
Instantaneous Speed
It is defined as the magnitude of the instantaneous velocity that is derivative of the position concerning time.
V = |v| = |dr/dt |
Average Speed:
The total distance covered by any object divided by the total time interval
Average Speed = Distance Traveled / Time of Travel
Rotational Speed:
It is also known as rotating speed. In simple words, the rotational speed is the number of turns taken by a body in unit time.
Tangential Speed: rotational speed X radial distance; (V=rω)
Types of Speed
- Uniform Speed: If any object is covering the distance in equal interval of time is called uniform speed. For example, if the speed of the car is 20 m/s, it means the car covers 20 meters in two seconds
- Non-uniform Speed: If any object travels with varied speed and not covering the same distance in equal interval of time.
What is Velocity?
Velocity is defined as the rate of change in the position of any object with respect to time, it is physical vector quantity thus, it has magnitude and direction both
Velocity = Displacement / Time = ( final postion -initial postion ) / Time
Types of Velocity
- Constant Velocity: If the velocity of an object does not change with the speed and direction and moves along a straight line is known as constant velocity.
- Changing Velocity: If the velocity of an object is changing with the speed and direction, it is also known as acceleration.
- Instant Velocity: Speed and direction changes at a particular time is called instant velocity.
- Terminal Velocity: hen the gravity takes over an object and results in falling down of the object towards the earth through the atmosphere is called terminal velocity.
Understand Velocity and Speed through Example
Let us suppose, I travelled 150 km in 5 hours, then what is my speed, as we know the formula to calculate the speed is Distance / Time; 150 / 5 =30 kmph. Now next is what is my velocity, in simple word, the varying speed is called velocity. while travelling my car initial speed was zero and it was being increased and decreased during the turns, on whole, the speed was not same which means I travelled with velocity to cover 150 km distance in 5 hr.
