Swimming: how it Works?

Swimming is a popular sport for competition or leisure, which a person must propel themselves through the water using their body and limbs. There are many forces that deals with the action of propelling yourself through the water. Techniques that are often used with swimming are; breaststroke, free style, back stroke, and the butterfly stroke. Newtons first law of motion or it is called the law of inertias.

This is explained as an object at rest will remain at rest and an object will remain in motion if its in motion, it will stay at the same speed and stay in the same direction it was going unless it is stopped by another force.

You will not keep accelerating because a force is pushing on you, therefore you must keep moving and using your legs and arms to push the water away from you. Pushing yourself off a wall in a pool will change the speed, also the weight of the water is pushing against you and will eventually make you stop if you don’t act on it. 

Why We Float: Buoyancy

In order for someone to float you need to understand Archimede’s principal. Archimedes wasa Greek scientist in the third century B.C. His principal states that rather or not your body is partially or fully submarged in water you will push water down and also up, then gravity will push that water back up on you with the same amount of force that you pushed it. So therefor the equilbrium of both forces will make you float. Not everyone can float however in order to do so, a person must also be less dense then the water. The denser a person is means the closer the atoms are. This means a person that has more muscle will sink and a person with less muscle mass or more body fat will float.

As stated in the physics fundamental textbook, density is the measurement of how much mass occupies a given space, it is the amount of matter per unit volume. (Hewitt, pg133). While swimmimg you actually have a center of boyancy which means your center of mass is by your belly buitton and your center of volumn or center of buoyancy is by your lungs. This is because the air that is in your lungs is not dense at all which will make a person float. Have you ever tried going to the bottom of a pool or lake and and sitting on the floor or even sitiing in an upside down position, what happens? Your body automaticlly tries to force you back up in the upright position and to the surface due to the air in the lungs. https://www.real-world-physics-problems.com/physics-of-swimming.html

Hewitt, Paul. Conceptual Physics Fundamentals Friction: Motion Swimmers often experience friction drag. This is because the force of water is pushing back at them. As you are moving your body you use more energy to propel yourself through the water to accelerate faster. An example would be someone that wears t-shirt and shorts rather then someone in a speedo. The person that wears the looser fitting clothes will need to work harder to swim faster because the clothes are also weighting the person down and pulling on them along with the water.

Pressure from Water Not only does a swimmer experience friction drag, they experience a pressure one also. What this is a swimmer and their body shape displace water. The water behind the swimmer has less water pressure then the water in the front of them. The faster you are when swimming will give you more resistance from the water pressure that is build up in the front of you. Impact Strength Ever wondered why the water feels harder upon impact the higher you are above the water when you hit it verses stepping into a pool within inches of the surface? Or hear of someone saying that hitting water after going a certain speed will make it feel as if you are hitting cement.

This is because of gravity as well as kinetic energy. As an object or person falls, it creates kinetic energy that is moving all around that object in all different directions. Kinetic energy is an energy a person or object may have due to its motion, it also depends on the mass of the object as well as the speed. Kinetic energy is equal to the mass multiplied by the square of the speed its going, then multiplied by the constant ?? (KE=1/2 mass x speed^2). If a person depends on jumping out of a plane at 2,500 feet, then you will be accelerating first for 2,000 feet then the next 500 feet you will be considered at terminal felicity. Which then would make the water that will be pushing up at you about 300 plus m/h.

Terminal felicity is the maximum amount that you can achieve during free fall. This also will depend on the way you fall, vertically or horizontally. An object in free fall will accelerate at around 10m/s^2. The greater the mass of an object the greater the pull it will have while accelerating. https://www.quora.com/What-happens-if-a-person-free-dives-on-the-ocean-from-a-helicopter-2-000-feet-above Drag: Slow vs. Fast Force = Mass x Acceleration is part of Newtons second law of motion. For swimming this is explained by the force of the swimmer is equal to the mass of the person then multiplied by how fast the person swims. This will also tie into the first section of how swimming works. Take the last part where I used an example of someone pushing off a wall of a pool.

If there were two people competing, they both have the same mass as each other and have them just use their legs to push themselves off the wall with out using their arms for help. The person who uses the greatest amount of force to push themselves off the wall would accelerate much faster than the person who did not. An example would be F=MA, so both swimmers would weigh 90kg. Person A takes off at 2 m/s while person B takes off at 2.5 m/s. For person A you would take 90kg x 2 m/s, so F=180N. Person B would be 90kg x 2.5 m/s so the force for B would be 225N. In Newtons Third law of motion he states that when you push water then the water pushes back on you.

You have two forces that are acting on you at the same time, a frontal drag and a propulsive drag, or you might say drag force and thrust force. These two things are constantly acting on each other. The only way to swim faster is to reduce the frontal drag or increase the propulsive drag. When you speak to competitive swimmers you hear of them shaving all the hair off their body to help in reducing the frontal drag. Some might even wear a suit that is considered a fast suit because of the way it is made and how it forms to your body. My father use to compete in swimming and he always said it was also in how you position your hands, fingers and feet. These things all could play a role in improving your speed.

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