Tuesday, June 03, 2008

Acceleration (Fun with Physics)

Which has a faster acceleration? My 300+ hp car, or gravity? (ignore the different planes in which they operate)

The question came up today because I was joking with Dave K. that my old 48hp 1980 VW Rabbit Diesel accelerated from 0-60 mph in under 5 seconds - then I clarified "off a cliff". Hence the debate.

Gravity seems to be such a weak force. I mean if I drop a tennis ball no one points how how that ball just peeled out of my hands. So how fast would gravity accelerate you from 0-60 mph? Is it faster than my car which goes 0-60 mph in 5.1 seconds? It turns out that gravity is pretty darn fast (accelerationally speaking). For those science geeks I will be referring only to gravity here on earth.

Here are the numbers (G = force of gravity)

2008 BMW 335xi     0-60 in 5.1 s ~ 0.55 G
2008 "Gravity car"   0-60 in 2.7 s    1.00 G

Turns out an F1 race car can pull 1 G accelerating, but if you want to talk fun facts, the same race car can pull 5 G's braking!!!!1 It can go from 200-0 in 1.9 seconds or 180 ft! That is amazing!

A human can accelerate at about 0.4 G's running the 40 yd dash
The space shuttle takes off with 3 G's
A 1997 Dodge Viper can go 0-60 in 2.9s or 0.94 G's
A falcon can pull 18 G's pulling up from a dive!

Other fun fact:
In 1954 Col. John P. Stapp rode a rocket sled to 632 mph in ~6 seconds and then came to a stop in 1.4 seconds. He experienced deceleration forces averaging 25 G's with a 40 G peak!

(since I rarely post 2 blogs on the same evening, be sure to check out the Shelby modeling blog below!)

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