Is the change of change in acceleration always constant?

Yes there are higher derivatives. Only the first two are well known. The rest do exists. They are not always constant. Jerk: The change in acceleration is known as Jerk. (3rd derivative of a position vector with respect to time). It is exactly what it sounds like. If you're in a train, and the acceleration is smooth, you're fine. read more

Constant speed = 0 acceleration Constant acceleration = constant change in speed. E.g. when getting on a highway Change in acceleration = slowing down and speeding up at different rates. E.g when getting on highway you have positive acceleration, then you go at constant speed (0 acceleration ) Change in that would be change in how fast acceleration was changing. read more

In physics, when an object travels in uniform circular motion, its speed is constant, which means that the magnitude of the object’s velocity doesn’t change. read more