If every action has an equal and opposite reaction, how come an object dropped from a certain height doesn’t bounce back to the original height?

Question

If every action has an equal and opposite reaction, how come an object dropped from a certain height doesn’t bounce back to the original height?

In: Physics

Answer 1

So first of all, when you drop an object it accelerates equal to the gravity of earth minus the slowdown caused by air friction. When it hits the ground the object will, under perfect circumstances, impart all of its momentum into the ground. If the ground can give way then some of this momentum is lost. If it can’t then all of the momentum will be pushed back the other direction; it’ll bounce.

Now, when the object is going back up though, gravity AND air friction are both slowing it down.

So the end result is that the action does have an equal and opposite reaction, you just didn’t consider some of the opposite reactions.