Today, I encountered the problem where I was asked to find the velocity and acceleration from displacement-time graph but the displacement-time graph was discontinuous. So I am unable to find the velocity where it was discontinuous.

I know from my Calculus class that we **cannot find the derivative when function is discontinuous** at some point.

**So I think it's not possible to find the velocity and acceleration at that point.
So what is the physical significance of that?**