Twisting physics of cats

Answer: Without having anything to push off or twist against, the cat extends its rear legs and twists the front half of its body toward the ground, says Exploratorium.edu. Its rear half rotates the opposite way, but not as far, thus conserving angular momentum. Then the cat extends its front legs and twists its tucked rear legs toward the floor. "By repeating these motions, the cat may gain sufficient net rotation to land with its paws on the ground."

Miscellaneous aside: "I have had physicists tell me that cats without tails cannot do the trick," says University of California-Santa Cruz mathematician Richard Montgomery. "This is false. Manx cats can do it fine. One computes that if the trick were due to the tail, it would have to whip around about 50 times to flip the cat."

Flexible humans can rotate with no angular momentum as well, says Harvard physicist Eric Heller. NASA has video of astronauts starting stock still, then rotating outstretched arms to alter body orientation. "I once saw an astronaut scissor his legs so as to wind up 90 degrees rotated."

Question: How big has the "Big Swing in Gender Roles" been over the last half century?

Answer: It's been dramatic, says David G. Myers in "Social Psychology," as people approving of a married woman earning money in business or industry has gone from 1 in 5 (Americans, 1938) to 2 in 5 (1967) to 4 in 5 (2002).

The percentage of 40-year-old married women in the workforce went from 38 percent (1960) to 75 percent (1999 — the U.S., Canada, Britain, Australia). The percentage of female Harvard Business School graduates went from 0 percent (1965 — had never graduated a woman) to 30 percent (2000). The proportion of women U.S. medical and law school graduates went from 6 percent and 3 percent (1960) to 43 percent and 45 percent (2000).