A skateboarder is inside of a half-pipe, shown here. Explain her energy transformations as she jumps off at point A, slides to point B, and finally reaches point C.

At point A, the skateboarder’s energy is all potential since she is high up (PE = mgh), and gravity has the potential to pull her down. She isn't moving, so she doesn't have velocity. Therefore, she doesn't have kinetic energy. At point B, she is moving the fastest during her ride and is as close to the ground as the ramp allows. Thus, her potential energy has been turned into kinetic energy due to her velocity and lack of height. At point C, if she comes to a stop on the other side of the half-pipe, her kinetic energy has been turned back into potential energy since she is high up again.

Eventually, the friction between the wheels and the ground will cause the skateboard to stop. Each time she goes back and forth, she will lose some of her initial energy from her drop-in, as long as she doesn't push off the sides at all.

Explanation:

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8