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# Physics of Hula Hooping

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Hula hooping was a big part my childhood, I mean I literally had a gym unit on hula hooping in grade school. But ever wonder how it works? Well the answer is Physics.... big shocker there. The spinning of a Hula Hoop around a person's hips can be attributed to several forces (1) you as an upward force (2)gravity as a downward force (3)torque as a spinning force) and (3) friction which acts in opposition to torque..... The person moving their hips inside the hula hoop is exerting an upward force upon the hoop which is propelling it upward. This motion of pushing up and pushing out which is caused by the hula hooper's hips creates torque. Torque is a twisting, outward force not to be confused with the force of: twerk. Torque is needed in order to make the hula hoop spin around you. Or if you want to get fancy- it's the force needed to keep the centripetal force going. Another force involved in Hula hooping is friction. The friction between the hoop and the persons clothes and the air slows the hoop's spin down. So if you're terrible at hula hooping and you can't get those really fast spins going for a long time just blame friction. However, if you did this, you would be neglecting the fact that friction also helps keep the hoop in the air by acting in opposition to the force of gravity which pulls the hoop down. Now keeping all this in mind... let's talk sabotage. if you challenge someone to a hula hooping contest offer to provide the hula hoops and give them a hoop with a greater weight then yours. With more weight, the heavier hula hoop will be pulled down more then the lighter one and therefore need more torque to act in opposition of gravity in order to keep the hoop up. This heavier hoop will probably spin much slower then yours if you applied the same amount of force to the heavy one as you would normally to a light one. So the amount of force needed to keep the hula hoop spinning depends on the weight and mass of the hoop along with other factors such as how well it fits around your waist. You can also make sure their hula hoop is wayyy to big for their waist which will led to a slower speed then a smaller hoop because it takes more time to make a full spin around the hips. Or if you want to be extreme you can also travel to a planet with a smaller gravity then earth's and hula hoop there while making your opponent stay on earth. With less of a force pulling downward on your hoop you're sure to win. Sadly, the hula hoop will not spin forever, friction will eventually slow it down to a stop as it does to a rolling ball for example.(not to mention the fact that you would get tired of exerting an upward force with your hips).... But neglect friction, hula hoop with less gravity and sabotage your opponents hoop and you my friend are a HULA HOOPING CHAMPION

## 1 Comment

I love the science and that is what I am researching to add to my classes. However the use of hula hoops will will prove the flaw in your theory of sabotage.

It is actually easier to use a larger heavier hoop on body because it moves slower and gives better awareness of when you need to add force to keep it moving. That being the case it offers a better allowance for making mistakes but requires a larger slower movement. Smaller lighter hoops require a quicker smaller movement and more body awareness.

You can have a hoop that is too big. However most people (adults and children) who are not experienced with hooping find my mega hoop measuring in at 5 feet in diameter and weighing apr 1.5 lbs easiest to use versus the dollar store hoops that are 2 feet in diameter and weight less than 0.25 lbs. The best hoop for a beginner should come to their chest and weigh between 0.75 to 1 lb. Using a heavy hoop (over 3 lbs) can cause back problem by pulling your spine out of alignment and cause bruising.

So if you truly want to win that contest and do it quickly, pick a hoop that comes to your chest that weighs around 1 lb and give your friends a hoop from the dollar store.

By the way, I am a certified Hoopnotica hula hoop instructor and have been hooping for over 5 years.

If you want to experiment with different sizes of hula hoops you can make your own out of irrigation tubing. instruction link-

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