Friction, then, and gravity plays a vital role in creating the friction. Thanks for helping me understand all this!
By the way, you might enjoy this video of running on ice:
Thanks for the response.
Understood. If you look at the initial condition and final condition, no change in distance from the center of the Earth means no change in gravitational potential, no net gain of energy from gravity.
When you run, your center of mass oscillates up and down. It...
Archosaur,
So if you drop a pogo stick that is oriented at an angle to the vertical, will its rebound include a horizontal as well as a vertical component?