The Third Derivative Of A Relationship

This is a brilliant physics pun that operates on multiple levels! In physics, position's derivative gives velocity, velocity's derivative gives acceleration, and yes—acceleration's derivative gives us "jerk" (the rate of change of acceleration). So when she texts him about derivatives and he doesn't respond, she calls him a "jerk"—which is both an insult AND the exact answer to her question! The third derivative of position with respect to time is literally called "jerk" in physics. Talk about a relationship with too many variables and not enough constants!