How does timing and spacing affect the perceived weight and realism of animated elements?

Example Concept: Timing refers to the speed of an animation, while spacing involves the distance between frames. Together, they create the illusion of weight and realism by controlling how quickly or slowly an object moves and how it accelerates or decelerates. For instance, heavier objects may have slower timing and more gradual spacing changes to simulate mass, while lighter objects can move quickly with more abrupt spacing shifts.