Monday, May 10, 2021

How about a little free fall after a math lesson?


For some high school students in the Dallas-Fort Worth area, indoor skydiving was a reward for doing well in school in terms of grades and attendance, the Star-Telegam reports.

After spending some time at the iFLY Fort Worth indoor skydiving facility, Nisha Dalal, a senior at L.D. Bell High School in Hurst, Texas, told the paper she wants to study neuroscience or physics. “I’m definitely going to jump out of a plane. I loved the thrill of being weightless and the air coming at me,” she said, referring to the two-minute experience inside a wind tunnel.

A few companies—Dalworth Restoration and Dalworth Clean—and the nonprofit organization 6 Stones came together in order to provide funding for about a dozen students who were doing well in school but couldn’t afford the indoor skydiving fees.

“We wanted to work with kids who are doing well but have some odds against them,” the paper quoted Josh Hobbs, chief information officer for Dalworth Restoration, as saying.

Prior to the skydiving experience, students had to sit down for a lesson about safety and a little bit about the math and physics behind skydiving: gravitational acceleration, terminal velocity, drag, etc.

Terminal velocity is the speed at which the drag from air molecules hitting a free-falling object, like a penny dropped from a skyscraper or a skydiver jumping out of an airplane, is opposite in direction but equal in magnitude to the gravity acting on that object.

  • A physics explanation of terminal velocity (Georgia State University)
  • Terminal velocity of a 165-pound skydiver (pretty dense): about 134 mph
  • Terminal velocity of a 1.6-ounce golf ball (lower density): about 72 mph

But before reaching terminal velocity, a skydiver’s in free fall for maybe about 30 seconds and experiences “apparent” weightlessness. A free-falling object isn’t weightless, since gravity is acting on it continuously, but if the object is, say, inside a spaceship, things would float.

This explains how movie makers shoot scenes, like in Apollo 13, where objects are floating around. The actors are inside a free-falling module, and the scenes have to be shot 30 seconds or so at a time.

NASA also uses this type of module to train astronauts, and the agency calls the module a “vomit comet,” since those riding in it really do experience apparent weightlessness.

Paul Katula
Paul Katula is the executive editor of the Voxitatis Research Foundation, which publishes this blog. For more information, see the About page.

Recent Posts

Md. to administer tests in math, English

Students in Md. will still have to take standardized tests this spring in math and English language arts, following action of the state board.

A week of historic cold and snow

Perseverance lands on Mars

Summer vacation, summer job, or summer school?

Biden is sworn in as 46th president

Florida balances optimism after the riots