Brain Teasers
Space Race
If planet A is circling the sun at 5000 miles per hour, and is 30,000 miles from the sun, how fast does planet B have to go to keep up if it is 50,000 miles from the sun?
Hint
Circumference of a circle = 2*pi*radiusAnswer
8333 miles per hour.Because circumference of a circle is first order, 2*pi*r, the ratio can be set up: 5000/30000= X/50000
5000*50000/30000= 5000*5/3= 25/3*1000= 8.333*1000= 8333. No calculator needed!
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Comments
Easy enough assuming circles, but a planet's orbit is actually elliptical.
I'll grant the circular orbit for the sake of simplicity in the teaser.
To me, the fatal flaw is that the teaser violates Kepler's laws of motion. Unless the outer planet is under power, there is no way it can have that orbital velocity. *Especially* in the case of assumed circular orbits, the cube-square law dictates the orbital periods of all planets in the system, and they most decidedly canNOT keep pace with one another unless they're in the same orbit and dynamically balanced (diametrically opposed or in a trojan-point relationship.
To me, the fatal flaw is that the teaser violates Kepler's laws of motion. Unless the outer planet is under power, there is no way it can have that orbital velocity. *Especially* in the case of assumed circular orbits, the cube-square law dictates the orbital periods of all planets in the system, and they most decidedly canNOT keep pace with one another unless they're in the same orbit and dynamically balanced (diametrically opposed or in a trojan-point relationship.
Aw heck, there's always a party-pooper in the bunch.
Ditto.
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