The following is a post from contributing writer Marci.
Today, we are going to look at a little circus science. Behind the acrobats, trapeze artists, and jugglers, the laws of physics are at work. Let’s look at the physics of the trapeze.
One of my favorite circus acts was always the flying trapeze. Watching the talented acrobats swinging high up in the big top, then becoming airborne, flying gracefully and terrifyingly through the air, only to be caught by another trapeze just as their flight started its decent, was thrilling for all.
I didn’t have a trapeze growing up, but I did have a swing. I used to swing for hours. Sometimes, I would pretend I was swinging from a trapeze bar high up in air.
When I was on my swing, sometimes I would get started with a push from mom or dad. Other times, I had to pump with my legs to get going. If I wanted to keep swinging, I quickly learned I had to add some more energy of my own. I didn’t know it then, but I was experimenting with the laws of physics.
Trapeze Artists Are Full Of Potential (Energy, That Is)
Let’s look at the trapeze and swing as a simple pendulum. The pendulum is a weight hung from a fixed pivot point that is allowed to swing freely back and forth in an arc. When a trapeze artist stands on the platform holding the trapeze bar, they are the weight. This will allow us to make some calculations regarding the trapeze.
When the trapeze artist is still on the platform, the artist contains the maximum amount of potential energy. The moment they leave the platform holding onto the trapeze bar, their potential energy decreases. However, as their potential energy decreases, their kinetic energy increases.
This trend continues until the trapeze artist reaches their lowest point of their swing. At this point, the potential energy equals zero and the kinetic energy is at its maximum. All the potential energy has been converted into kinetic energy. Speed is also at its maximum.
As the trapeze continues past the low point and starts the second half of its swing, the reverse happens. Kinetic energy decreases and potential energy increases until the trapeze reaches the top of its swing range and stops momentarily. At this moment, potential energy is at its maximum again and kinetic energy is at zero. The kinetic energy has been converted back into potential energy.
Test Your Energy Levels
Go outside and swing. Think about the potential energy you have at the top of your swing when you make that momentary stop. Then, think about how all that potential energy has been converted to your maximum level of kinetic energy at the bottom part of your swing. Think about how fast you are going at that point.
Circus Physics Links
- Circus Physics Videos and Study Guides from PBS
- The Physics of The Flying Trapeze
- The Physics of The Circus from students at the University of North Carolina
Science is everywhere! Even at the circus.