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The radius of a planet is R1, the autobiographical period is T1, it has a satellite, the orbit radius is R2, the cycle around the planet is T2, if the gravitational constant is g, find the average density of the planet
Gravity provides centripetal force: GMM / r2 ^ 2 = m * R2 * (2pi / T) ^ 2 can get m =
If the radius of the planet is R1, the volume v = 4 * pi * R1 ^ 3 / 3;
Then the density p = m / v
If M1 = 2M2, R1 = 4r2, the ratio of their periods T1: M2 is 1:1
The masses of the two planets are M1 and M2, and their orbital radii around the sun are R1 and R2, respectively, if M1 = 2M2
, R1 = 4r2, then what is the cycle ratio T1: T2
Kepler's law, a cubic / T is constant, circular orbit, semimajor axis a = R, so T1: T2 = (R1 / r2) ^ 3 / 2 = 8
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- 2. The two forces acting on the same point are F1 = 5N and F2 = 4N. If the angle between the resultant force F and F1 is θ, then θ may be () A. 45°B. 60°C. 75°D. 90°
- 3. When the horizontal thrust f acts on a, the two objects move together, and the pressure between AB is F1 When the horizontal thrust f acts on a, the two objects move together, and the pressure between AB is F1; when the thrust f acts on B, the two objects move together, and the pressure between AB is F2, then () The acceleration of two motions of a is equal BF1 + F2
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- 7. A body is forced by F 1 = 6N to produce an acceleration of a 1 = 3m / S 2. How much force should be applied to make a 2 = 9m / S 2 acceleration
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- 11. If the mass ratio of the two planets is M1: M2 = P and the orbit radius ratio is R1: R2 = q, then the ratio of the two planets to the sun's gravity is F1: F2=______ ．
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