On this episode of Physics of swimming we will go over Kinetic and potential energy and why I think Adam Peaty is like a cobra. You can think about the physics of moving objects in two different and equally acceptable ways: in terms of forces, or in terms of energy. In the past physics of swimming videos we looked at them in terms of forces, now it will be energy. Kinetic energy is the energy of motion (“kinetic” means motion) Potential energy is stored energy. Energy can be stored in chemicals, by compressing a spring, or by doing work against gravity. Ok so let’s bring it back as it relates
to swimming. When you are diving you have two kinds of potential energy. The first is gravitational potential energy. You convert that energy into kinetic as you are in the air and gravity brings you down to the water. This type of potential energy is found in
a smaller scale while you swim butterfly. When you lift your torso and arms above the surface, you convert kinetic energy into potential and then back to kinetic as you quickly are brought down by gravity. Then you pass that energy through your body and down to your feet through the undulating movement of the stroke, this movement then pushes the water backwards and pushes you forward. The second kind of kinetic energy you have on the blocks is chemical potential energy. Muscles act like springs, so the chemical
potential energy of muscles is converted, by the muscle applying a force, into kinetic energy of motion. So when you “take your marks” you stretch certain muscles as if you were stretching a spring. Those muscles have a lot of chemical potential energy which is transformed into kinetic energy as the muscles tighten and make you jump! That is why I think Adam Peaty is like a cobra. Because when he swims breaststroke he uses his back muscles and arms to lift his torso and head high above the water. This gives him gravitational potential energy, then just like a cobra he uses his core muscles to throw his upper body forward transferring that energy down to his legs. His legs are already full of chemical potential energy when he bends them and he uses all of that stored energy to push his body forward under the surface with a speed that only this human being can maintain through a 100 meters long course. So now you know! Swimming is all about the dance between these two types of energy and the forces that interact with our bodies. To learn more about the forces of physics
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