Hi Guys, I have a general question (not necessarily a homework question) about the concept of related rates in differential calculus. Most related rates problems present to you a question that generally asks, After x time has elapsed, or At t= __, what is the rate of change between __ and __? Suppose I have a related rates problems involving kinematics. At noon, object A is __units away from object B. Object A is moving in an opposite direction away from object B. Object A is moving at a constant rate of __units and object B is moving at a constant rate of __units. After 4 hours, what is the rate of change of the distance between object A and B. I am content with the premise. What captures my interest is the question. If two objects are both moving opposite one another at a constant speed, wouldn't the distance between them be changing at a constant speed as well? Why would the derivative of the distance between the objects with respect to time be different after any time?