## September 19, 2005

### Superman's leaping ability

So, I was reading Wired magazine at lunch today, when I chanced upon an article about the physics of super-heroes. It seems a professor here at the U of M, James Kakalios, has written a book (The Physics of Superheroes) that discusses whether or not they obey the laws of nature. Nifty. Anyway, in the article they ask Kaklios about Superman's ability to "leap tall buildings in a single bound." Here is what he says:

Let's say a tall building is about on-eighth of a mile high -- his legs must exert about 6,000 pounds of force against the ground. Superman's muscles and skeleton are adapted to Krypton's gravity, which is much stronger than Earth's. If 6,000 pounds is about twice his weight on Krypton, and he weighs about 220 pounds on Earth, then the gravity on his home planet must be roughly 15 times greater than it is on ours.

How cool is that? Krypton has a gravity 15 times that of Earth's!!! See, that is why you read this blog, for important information like this. No need to thank me. Just go about your daily business. See you tomorrow!

Posted by snackeru at September 19, 2005 4:19 PM | Stuff I wonder about

Ummm.... how does he fly???

Posted by: SBG at September 19, 2005 4:57 PM

Anyone else think that Ziggy's egregious stadium proposal just torpedoed all three teams' stadium hopes? 675 million for a stadium in the middle of nowhere, that will only host 8 NFL games a year? Nice Ziggs. Justifying the stadium as the Minnesota answer for the 2020 Blaine Olympics or all the youth soccer tourneys that will be played there is downright laughable.

Posted by: Vince at September 20, 2005 1:15 AM

I enjoyed Dr. Kakalios' book, however the physics of Superman leaping tall buildings was flawed. The takeoff velocity to make the collosal jump of 660 feet was correct but the acceleration in order to make that leap was way too low. To jump 660 feet vertically is (h*G*2)^.5 or (660*32.2*2)^.5 which is 206 feet/second. Superman has to reach this velocity in only three feet. The acceleration required is v^2/(2*h) or 206^2/(2*3) or 7072.667 feet per second. Add 32.2 feet per second for the force of gravity of Earth for a total of 7104.867 feet per second^2 which is 220.65 times the gravity on Earth. The traditional gravity on Krypton has been over 30 times earth, that was when Superman could only jump a 100 foot tall building in a single bound which worked out to 80 feet per second and Krypton being 34.33 times Earth's Gravity. Superman has gotten stronger since then.

The subject of superman physics has been covered in 1987 as an article in the Hardcover copies of SUPERMAN AT FIFTY:
The Art and Science of Leaping Tall Buildings
by John McGervey

The best high jumper in the World gets a vertical liftoff of 16 feet per second with a force of 2.33 times his own weight. The vertical leap is 4 feet, the high jump is your center of gravity (about half your height on average) plus your vertical leap.

Spiderman's vertical leap of 30 feet requires strength 30 times his weight and a speed of 44 feet per second.

Hulk's vertical leap of one mile requires 1760 times his weight and 583 miles per hour, which works out to about 1000 tons instead of the 100 tons normally attributed to the Hulk. Hulk will also hit the ground at that speed creating a force of about 3 tons of TNT. If Hulk can get about 3.7 times stronger, he can hit the speed of sound and the 3.7 mile vertical leap.

Posted by: Robtius at October 28, 2005 1:58 PM

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