Key Equations

Sections
Key Equations

Key Equations

Kepler’s third law T 1 2 T 2 2 = r 1 3 r 2 3 T 1 2 T 2 2 = r 1 3 r 2 3
eccentricity e= f a e= f a
area of an ellipse A=πab A=πab
semi-major axis of an ellipse a= ( r a + r p )/2 a= ( r a + r p )/2
semi-minor axis of an ellipse b= r a r p b= r a r p
Newton’s second law of motion F=ma=mg F=ma=mg
Newton’s universal law of gravitation F=G mM r 2 F=G mM r 2
acceleration due to gravity g=G M r 2 g=G M r 2
constant for satellites orbiting the same massive object r 3 T 2 = GM 4 π 2 r 3 T 2 = GM 4 π 2