When we stretch a spring, which two factors affect how much elastic potential energy is stored in it

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Where is the potential energy throughout the loading, cocking, and releasing of the trebuchet?

How to calculate voltage drop in a series circuit