How can I draw an energy transfer diagram for weight lifting?
It actually begins (we may not even be able to say where it truly begins) with nuclear energy in the sun, but let’s skip until all the energy is in the human. The weightlifter (let’s pretend she’s female) eats food which contains chemical energy (that is why she ate the day before). Her digestive system metabolizes this chemical energy such that some can be used for her muscle activities. However, much of it is rejected as heat given off to the surroundings. This is why she sweats during the workout. The energy which is used for muscle activities becomes work done on the weights. This work transfer of energy to the weights, simultaneously becomes kinetic energy of the weights in motion, and also gravitational potential energy as the weights rise. As the weightlifter relaxes her muscles, allowing the weights to come to rest, any kinetic energy of the weights becomes gravitational potential energy, as the weights reach their turning point. As she brings the weights to the floor, that gra
