# Why quantities in physics are always talking about rates? [closed]

I get the idea that physics wishes to study changes to discover new rules. But why is everything related to rates? Acceleration,Velocity? Could we use something else apart from these? What can you think of istead of velocity(rate) to describe motion? Why rates?

• Can you suggest an alternative? – Charlie Jan 7 at 11:40
• I can't that's why I'm asking! – Shadman Sakib Jan 7 at 11:51

• @ShadmanSakib yes, that's pretty much what the second fundamental theorem of calculus says ($f(b)-f(a)=\int_a^bf'(t)\,dt$, under suitable assumptions). The point is that sometimes we understand the rates better, so we use this to understand the change. Sometimes we understand the change better so we use this to understand the rate (for example, I know that Usain Bolt ran 100m in 9.58s. If I ask how fast do I have to run to beat him, then this is clearly a situation where I understand the change better. Using this I can calculate the rate: I have to run faster than 100m/9.58s) – peek-a-boo Jan 7 at 12:22