Lift for kids

May 2024

Q: You’re helping to draft a script for a children’s cartoon about aerodynamic lift. Flo and Bob are air molecules. They see that an aircraft wing is rushing toward them. The script starts: “Bob, this is our chance to be stars! When the wing reaches us, you’ll be swept over it, and I’ll be swept under. You’ll fly faster because the top of the wing is curved. I won’t fly as fast, but since I have less distance to travel, we’ll meet again at the end of the wing.” Bob dons a curious expression: “Why do we have to meet again, Flo? And what makes me fly faster? I don’t have propellers or little rockets.” What should the script have Flo say next?

Send a response of up to 250 words to aeropuzzler@aerospaceamerica.org. By responding, you are committing that the thoughts and words are your own and were not created with the aid of artificial intelligence. DEADLINE: noon Eastern May 16

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FROM THE APRIL ISSUE: Play ball! We asked you to assess the physics of preparing to pitch a baseball on the moon by practicing release points in a spacesuit on the mound at Wrigley Field.

WINNER:  The pitchers practicing their release in spacesuits at Wrigley Field accounts for the bulk of the spacesuits but does not consider a key factor that will change when playing on the moon — gravity. The acceleration due to gravity on the moon is around 1.6 meters per second squared compared to Earth’s 9.8 m/s2 (though some engineers may round to 2 and 10 m/s2). This much lowered acceleration due to gravity means a ball pitched on the moon the same as on Earth will travel much less vertically. Calculating an estimation of the difference in vertical travel can be done assuming same initial velocity and constant acceleration caused by gravity. Assuming these pitchers can throw at 90 mph (~40 m/s) and the pitching mound is 60 feet 6 inches (18.4 m) from the plate, it will take 18.4/60.5 = 0.3 seconds for the ball to travel. With the time traveled known, apply the equation for vertical displacement with an initial velocity of 0 m/s. On Earth, the displacement is -0.441 meters, and on the moon, it’s -0.072 m. The ball travels vertically due to gravity much more on Earth than it does if thrown the same way on the moon. To properly practice on Earth, the players should throw baseballs that accelerate less toward the surface. This could be achieved by throwing baseballs filled with some buoyant gas such as helium, which would offset the greater acceleration on Earth.

André Comeau, AIAA student member Boston
comeua2@wit.edu

André is on track to graduate with a Bachelor of Science in mechanical engineering next year from Wentworth Institute of Technology