*Gravitational And Planetary Rotation Flashcards
See the analytical geometry section of your calculus notes
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Kepler’s first law
Planetary motion takes the form…
1=(x/a)^2+(y/b)^2
Always an Ellipse
Gravitational fields
Negative gradient of gravitational potential
G=-∇P
See the section on vector fields and vector calculus
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Gravitational force between two objects
F=G(m1*m2)/r^2
Universal gravitational constant
G=6.67x10^-11
Keplers second law
The area inside the ellipse, the net space between the initial (a) and final (b) distances from the smaller to the larger mass, is equal to all other areas measured in the same length of time, regardless of the larger masses position within the ellipse.
Meaning the magnitude of the vector function at the final time (t) can be calculated through √(a^2sin^2(t)+b^2cos^2(t)). Integral of this is arc length. Derivative (acceleration) is proportional to the radius (r).
Kepler’s third law
Period of orbit (T) squared over average distance (d) cubed is known as the ‘orbital ratio’
Equal to those of similar average vectors
(T1^2)/(R1^3)≈(T2^2)/(R2^3)
Gravitational energy (uniform)
Ug=Fg(m)*r
Gravitational energy (non-uniform)
Ug=(Gm1m2)/d