Zero velocity updating
Whenever velocity is constant, the acceleration is zero.This also works when the velocity is zero, the acceleration is zero. But, yes/ If velocity is constant, accleration is zero.However, this would change the velocity to non-zero after any amount of time.An example of this is when you throw a ball into the air: at it's highest point, the velocity is zero (it changes from going…Zero acceleration means there is no change in velocity over time, namely constant velocity.Constant velocity can be any velocity (including zero velocity or "at rest"), so the object's velocity doesn't have to be zero to have zero acceleration.
If the velocity is zero, the acceleration is not necessarily zero. For example, if you throw a stone up, when it is at its highest point it has a velocity of zero, but its acceleration is -9.8 m/s2.
You could even have non-zero velocity and zero acceleration.
What seems impossible is to have zero velocity and non-zero acceleration.
So the new question is if that other person has zero velocity and…
As, in the velocity-time graph, curves passes through zero means 'when time is zero velocity is zero'. So displacement is maximum or minimum when time is zero in position-time graph.