Motion implies movement; it is the act of moving or more specifically, the change in position of the body, concerning time. Whenever you walk, run or drive you are actually in motion and not only this, flying of birds, swimming of fishes, flowing of water from the river, falling of leaves from trees, rotation and revolution of the earth, is also motion.
Velocity and acceleration are the two key concepts which are always discussed while studying motion. Velocity can be understood as the speed of a moving body in a particular direction whereas acceleration is any change in the velocity of the object, with respect to time. For a layperson, these two terms are one and the same thing, but in physics, there are subtle differences between velocity and acceleration.
Content: Velocity Vs Acceleration
|Basis for Comparison||Velocity||Acceleration|
|Meaning||Velocity implies the speed of an object, in the given direction.||Acceleration alludes to any change in the velocity of the object with respect to time.|
|What is it?||Rate of change of displacement.||Rate of change of velocity.|
|Ascertains||How fast something is moving and in which direction.||How fast the moving object's velocity changes with time.|
|Unit of measurement||m/s||m/s^2|
Definition of Velocity
In physics, velocity is described as a vector measurement as it has both magnitude and direction, wherein the magnitude represents speed and direction show its direction of motion.
Velocity is a physical quantity which describes the rate at which object moves, along with its direction. It implies the rate of change in position of someone or something, with respect to time, i.e. how fast an object displaces itself over time from one point to another.
One can change the velocity of the moving body, by making a change in its speed, direction or both. At any point, the velocity of the body is tangent to it’s path at that point.
Definition of Acceleration
A measure of change in velocity, with respect to time, is termed as acceleration. Whenever an object changes its velocity, it is said to be accelerating. It is a vector expression that has both magnitude and direction. An object is said to be accelerated when there is an increase or decrease in its speed or change in the direction of motion or both. It is concerned with how the body’s motion is changing with respect to time.
The change in object’s speed and direction are indicated by the component of acceleration, i.e. direction. When the direction of acceleration is parallel to velocity, then it is believed that object is accelerating or its speed is going up. However, when the direction of acceleration is anti-parallel to velocity, then the object is decelerating, or its speed is slowing down. Moreover, if the component of acceleration is perpendicular to velocity, then it reflects the amount of change in object’s direction. There can be two types of acceleration, which are:
- Centripetal acceleration: When the object travels at a uniform speed in a circular motion, like the revolution of the earth, then this acceleration is called centripetal acceleration because there is a change in the direction of the object.
- Tangential acceleration: When there is no change in the direction of motion but the speed changes with time, is called tangential acceleration.
Key Differences Between Velocity and Acceleration
The difference between velocity and acceleration can be drawn clearly on the following grounds:
- The velocity of an object refers to the speed in a specific direction. Acceleration implies any change in the velocity of the object with respect to time.
- Velocity is nothing but the rate of change of displacement. On the other hand, acceleration is the rate of change of velocity with respect to time.
- Velocity determines the speed of the moving object along with the direction of motion. Conversely, acceleration ascertains the speed of change in velocity of the moving object over a period of time.
- Velocity is calculated as displacement divided by the time taken in which it takes place. On the contrary, acceleration can be calculated as: change in velocity divided by the time taken while the change took place.
- The unit of measurement of velocity is meter per second (m/s) whereas the standard unit of acceleration is meter per second squared (m/s2).
- Both velocity and acceleration are vector quantities, which have both magnitude and direction.
- Both the expressions can be positive, negative and zero.
The motion of an object can be explained as distance traveled, which can be uniform or non-uniform, depending on the velocity of the object. The velocity of an object is its displacement per unit of time whereas acceleration is the rate of change of object’s velocity over a period of time.