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To: Jedi Master Pikachu
"What’s the formula (see some of the previous questions)?"

F=m*a. The acceleration(a) of gravity is:

aearth = F/m = g*mearth/rearth2

The planet is 5X as massive and the radius is 1.5X bigger, so:

aplanet = g*5*mearth/(1.5*rearth)2 = 5/1.52 * aearth = 2.2*aearth

Then see #104 and #106. The equatorial and polar radii are different, which would be due to spin. I just stuck a ruler up to the screen. A better measure(this AM, LOL) would be,

rpolar / requatorial = 1.083

A plastic body would find itself in a shape where the forces at the surface are equal. Since there's no spin at the poles, only at the equator, Equal surface scceleration gives,

apolar = aequatorial = 2.2(1-0.083) = 2.0

That means the centifugal acceleration at the equator is 0.2, and opposes the acceleration of gravity. So any mass m will be attracted to the surface with a force(F) of m*2*aearth

150 posted on 04/25/2007 7:57:24 AM PDT by spunkets ("Freedom is about authority", Rudy Giuliani, gun grabber)
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To: lepton
from the better guess of the planet's radii given in 150. The planet's angular velocity, or spin is ω=v/r. For Earth(e) and the planet(p) the radial acceleration(a) is:

a = v2/r

Where v is the tangential velocity of a surface particle. Then,

ve = sqrt(0.003*re*ae) = 0.055 * sqrt(re*ae)

and

vp = sqrt(1.5*re*0.2*ae) = 0.55 * sqrt(1.5*re*0.2*ae)

The ratio of the planet spins is ωp / ωe = (vp * re) / (1.5*re*ve) = 0.67*vp/ve

Substituting gives,

ωpe = 0.55/0.055 * 0.67 = 6.7

So, the planet spins 6.7 times faster than Earth, and it's days are 3.6hrs long. Since the period of one rev around the star is 14 earth days, it's probably not tidally locked.

160 posted on 04/25/2007 9:57:31 AM PDT by spunkets ("Freedom is about authority", Rudy Giuliani, gun grabber)
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To: spunkets
That means the centifugal acceleration at the equator is 0.2, and opposes the acceleration of gravity. So any mass m will be attracted to the surface with a force(F) of m*2*aearth

Thanks for showing the math there.

178 posted on 04/25/2007 2:51:51 PM PDT by lepton ("It is useless to attempt to reason a man out of a thing he was never reasoned into"--Jonathan Swift)
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