# Need of describing the term acceleration [duplicate]

What is the need of acceleration when we have velocity As I think velocity as 1m/s means 1m covered in 1s and 1m/s^2 means 1m covered in 1s per 1s this statement creates confusion when it comes to acceleration hence please tell the real purpose of acceleration?

• 1m/s^2 means 1m covered in 1s per 1s. No, you don’t yet understand acceleration. It tells you how fast the velocity is changing. What you wrote doesn’t make sense. – G. Smith Sep 23 '19 at 6:09
• "What is the real purpose of acceleration" is a metaphysical question -- why do we need anything in the universe? The reason that we need to handle it in physical problems is because if you have a finite force, and a finite mass, then you're going to have a finite acceleration. You can't just instantaneously impose changes in velocity on a mass: that leads to singularities (or infinities, same thing). – TimWescott Sep 23 '19 at 6:09
• You can have an idea with form into a relevant question.The values will solve the confusion. Pursuit physics.stackexchange.com/questions/20800/… That is the better way for understanding – Osal Thuduwage Sep 23 '19 at 6:11

Speed is the rate of change of distance with respect to time. 1 m/s means every second the distance increases by 1 meter.

Acceleration is the rate of change of speed with respect to time. 1 m/s/s means every second the speed increases by 1 meter per second.

You can plug those definitions to any computer program and never have to use calculus to get your approximate results to any problem.

• But in acceleration, second square is confusing me – user243076 Sep 23 '19 at 6:13
• 1m/s/s = 1m/s^2. It's fractional division. – dimachaerus Sep 23 '19 at 6:16
• But imagining such thing is too difficult – user243076 Sep 23 '19 at 6:17
• Okay well, you definitely can tell a difference between a car that takes 5s to get to 100 km/h speed and a car that takes 20s to do the same, right? – Ezze Sep 23 '19 at 8:18
• Yes I can tell the difference – user243076 Sep 24 '19 at 4:51

$$\rm acceleration = \dfrac{\text{change in velocity}\,(\rm m\, s^{-1})}{\text{time taken for change}\,(\rm s)}$$

The units of acceleration are $$\dfrac{\rm m\, s^{-1}}{\rm s}= \rm m\, s^{-1} \times s^{-1}=m\,s^{-2}$$.

Acceleration is a measure how much velocity changes with time in the same way that velocity is a measure of how much displacement changes with time.

You probably have no problem with the units of velocity because they are $$\dfrac{\rm m}{\rm s} = \rm m\,s^{-1}$$ and the numerator is just a single unit.

If the unit of velocity was the $$\rm "james"$$ then the unit os acceleration would be $$\rm james\,s^{-1}$$