The age of reason
From j.f. <_@gmail.com>
to P.K. <_@gmail.com>
date Wed, Mar 23, 2011 at 5:22 PM
subject "bird defense"
8.28. To protect their young in the nest, peregrine falcons will fly into birds of prey (such as ravens) at high speed. In one such episode, a 600 gram falcon flying at 20.0 m/s ran into a 1.5 kg raven flying at 9.0 m/s. The falcon hit the raven at right angles to its original path and bounced back with a speed of 5.0 m/s. (These figures were estimated by one of the authors (WRA) as he watched this attack occur in northern New Mexico.) By what angle did the falcon change the raven's direction of motion?
from P.K. <_@gmail.com>
to j.f. <_@gmail.com>
date Wed, Mar 23, 2011 at 5:32 PM
subject Re: "bird defense"
Wow, your physics homework is playing pool with birds?
I really did go and eat a bunch of French toast for lunch. It has helped.
—They’re having us figure out the center of gravity for objects that are bent in various ways. It’s ridiculous.
—The center of the donut is the hole.
—Yes. The book said that.
[...]
—So if there’s an axis of symmetry, you know the center of gravity will lie somewhere along it. The other coordinate is kind of a guess.
[...]
—At least crows are symmetrical.
—Ha! Thank you! I cannot think of a situation in which that knowledge would not be helpful!
—When you see half a crow, you can use your reason to infer the other half.
—By definition!
—When you see one eye, you know the crow has two eyes. When you see one tail, you know the crow has two tails.
was that a suicide attack?
i hope your fledgling understands you...this old bird does get the part about the french toast ;-)
