Difference between Velocity and Acceleration
Velocity and Acceleration are two basic concepts related to the motion of bodies in physics. These concepts may seem similar but they are different. Let us see how velocity differs from acceleration.
Velocity
Velocity is the rate of change of displacement of an object. In other words, it is the rate of change of position of an object while moving from one place to another place. It is a vector quality as it is defined by both magnitude and direction. The standard unit of velocity is m/s. So, it is basically the speed of an object in a particular direction, e.g. a car moving at a speed of 30 m/s in the northwest direction, 30 m/s is the magnitude of the speed while the “northwest” is the direction in which the object is moving. So, in this case, the speed is 30 m/s and the velocity is 30 m/s northwest.
It shows two objects moving at the same speed may have different velocity if they are moving in different directions. For example, two cars are moving at 20m/s along the same road but in opposite directions, north and south.
Formula = Displacement / Time (m/s)
Acceleration
Acceleration is the rate of change of velocity per unit of time, in other words, the increase or decrease in velocity over a period of time. It is a vector quality, defined by both magnitude and direction. In SI units, it is measured in meters/second2.
So, acceleration occurs when there is a change in velocity, e.g. Either speed or direction of a moving object changes in relation to time. It is the net force acting on an object which causes it to accelerate. Thus, it is the derivative of the velocity ‘v’ with respect to time’t’: v = dv/dt
Formula = Velocity / Time (m/s2)
Acceleration mainly measures how fast or slow a moving object speeds up as it travels from one point to another point. To accelerate an object needs the application of force.
Based on the above information, some of the key differences between velocity and acceleration are as follows:
| Velocity | Acceleration |
|---|---|
| It is the speed of a moving object in a specific direction. | It is the change in the velocity of an object over a period of time. |
| It is the rate of change of displacement, how an object changes position while moving from one place to another place. | It is the rate of change of velocity of a moving object. |
| Formula = displacement/time (d/t) | Formula = velocity/time (v/t) |
| It does not require net force acting on the object. | It requires net force acting on the object. |
| An object having a velocity may not have acceleration. | Every accelerating object has a velocity. |
| It requires speed and direction of the moving object. | It requires a change in the magnitude or direction of the velocity. |
| It tells how fast an object is moving and in which direction. | It tells how fast an object’s velocity changes with time. |
| Unit of measurement: meter/second (m/s) | meter/second2 (m/s2) |