# The Physics of Skydiving

by Ashley Hazel AP Physics 1 Student

Every one has heard of the extreme sport of skydiving, yet does everyone know the physics involved with it? Physics plays a monumental role in every aspect of our lives, and for this intense hobby, physics dishes up a major dose. So let’s break things down.

The first jump.

Once you leave that plane, your heart is racing, your palms are sweating, and probably the only thing on your mind is “Ahh!.” But, have you ever stopped to think about what’s going on around you as you joyfully plummet towards the ground? As you are capturing those Instagram-worthy Go-Pro selfies, there are two forces acting on you: gravitational pull and friction with the air. As you leave the plane, Earth’s gravitational pull will carry you straight towards the ground, and you’ll gain speed with each second. While you begin to travel, the resistance from the air around you begins to increase and pushes up in the opposite direction of your fall (luckily it’s not as strong as gravity). Thanks to the relationship between gravity and air resistance, you won’t keep falling at a rapidly increasing speed, but as your speed increases, so does air resistance. The air resistance will keep increasing until it reaches the magnitude of the force of gravity. Once this happens, the forces become balanced, and you’ll no longer accelerate.

Body Position

Ever heard of the term aerodynamics? Well, it plays a major role in skydiving, as well. The position and shape of your body dictate your speed as you fall. For example, say you and your friend decided to race down. You go with the method of tucking your arms and legs in as tight as you can into your body. Your friend, on the other hand, decides to go full flying squirrel. You’ll notice that as you fall, like the graceful armadillo you embodied, your friend will lag behind you because of the difference in body positions. Your stretched-out friend has more surface area than you do. Air resistance has a greater surface to work on, thus slowing the body down. However, while you might be the speedy one of the group, stretching out while falling is actually a better skydiving technique because this position creates dynamic stability – keeping you more stable as you descend.

The Parachute

Now comes the moment of truth: the parachute. This simple little device holds the most important job of all-SLOWING YOU DOWN. But how? The answer is simple, air resistance. Just as your body position controlled your speed, the parachute’s broad surface area works to keep you from regretting your spontaneous skydiving adventure. The parachute’s huge size proves vital and is the sole reason you can significantly slow down to a speed that promises safety. This significant change in speed is why you always see the huge snap up once the parachute has been released. The huge amount of air being trapped by the parachute causes a dramatic slowdown.

Skydiving is no joke and neither is the physics involved with it. These forces that so many of us remain unaware of are responsible for so many great things in the world. Physics allows us to jump out of planes safely. I mean what else can do that, right?!? So maybe if you ever work up the nerve to go skydiving you can stop and think about what’s really going on around you. Maybe even share it with your diving instructor. Your extensive and intriguing knowledge might even make up for that full face of hair you gave him during the jump.

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