Have you ever wondered, why different objects travel the same distance, taking different amounts of time? This is because some objects are faster than others. You can calculate the rate of motion of a body, by determining the distance covered by an object in a given interval of time, i.e. speed. The term ‘speed’ is often misconstrued with the ‘velocity’, because of having similar applications. However, these two are very different concepts of motion, in physics.
Velocity measures the distance travelled by an object concerning direction. As these two concepts move around the measurements related to the motion of the body, it is important to know the difference between speed and velocity.
Content: Speed Vs Velocity
|Basis for Comparison||Speed||Velocity|
|Meaning||Speed refers to the distance covered by an object in unit time.||Velocity refers to the displacement of the object in unit time.|
|Determines||How fast something is moving?||In which direction something is moving?|
|Quantity||Scalar quantity||Vetor quantity|
|Indicates||Rapidity of the object.||Rapidity and position of the object.|
|Rate of||Change of distance||Change of displacement|
|When the body returns to its initial position||Will not be zero||Will be zero|
|Moving object||Speed of moving object can never be negative.||Velocity of moving object can be positive, negative or zero.|
Definition of Speed
By the term ‘speed’ we mean that the distance an object travels in a definite time. It is a scalar quantity as we need only its magnitude, but not the direction to specify it. It can be understood as the rate at which a body travels distance, in the unit time. It determines the quickness of the object, i.e. how fast an object is going. Meter per second is the SI unit of speed. However, the most commonly used unit of speed is kilometre per hour.
An object whose moving speed is high, covers the large distance in less time. Unlike an object with a low moving speed which covers small distance, in the same amount of time. When an object does not travel any distance, its speed will be zero. You can calculate the speed of an object by applying the following formula:
Average Speed = Total distance travelled / Time taken
Definition of Velocity
Velocity is defined as the speed of a moving object in a particular direction. It is a vector measurement, as it contains both the components, i.e. magnitude and direction. Therefore while measuring the velocity of the object one must keep in mind that the direction should be specifically mentioned, with a view to explain velocity completely.
The velocity of a moving body is the rate of change of position, i.e. the displacement of an object with respect to the point of reference. To understand this, Suppose a car travels rapidly and returns to its initial position, the velocity will be zero because the car comes back to the original position and the motion does not lead to the change in position. In this way, the velocity of the car will be zero.
It is nothing but the speed of an object travelling in a particular direction. It can be uniform or non-uniform and can be changed with the change in the speed or direction or both.
Average Velocity = Displacement / Time taken
Key Differences Between Speed and Velocity
The points given below are significant, so far as the difference between speed and velocity:
- The distance covered by the body in a given interval of time is called speed. The displacement of the something in a definite time is called velocity.
- Speed determines how fast something is moving? On the other hand, velocity determines what direction something is moving?
- Speed is a scalar quantity, which measures magnitude only. As against this, velocity is a vector quantity which measures both magnitude and direction.
- While speed calculates the rate of change of distance, magnitude calculates the rate of change of displacement.
- Speed indicates the rapidity of the moving body. Conversely, velocity represents the rapidity and position of the moving object.
- As distance can never be negative, the speed too can never be negative. On the contrary, the displacement can be positive, negative or zero, the velocity can take any of the three values, depending on the point of reference.
- When the moving object returns to the starting point, average velocity will be zero, but this is not in the case of average speed.
- Measures how fast an object is travelling.
- SI unit is meter/second i.e. m/s.
Average velocity is always lower than average speed, except when the object is travelling in a straight line without U-turn, where the magnitude of average velocity, is equal to the average speed. Further, the velocity of the moving body changes with the change in direction.
Umema Jabalpurwala says
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