Calculating Orbital Period of Satellites

AI Thread Summary
To calculate the orbital period of a satellite using the radius of its orbit and the mass of the central object, the key equation is T^2 = (2π)²r³/GM. This formula derives from equating gravitational force and centripetal force, where G is the gravitational constant, M is the mass of the central object, and r is the orbital radius. The small mass of the satellite can be neglected in this calculation. The discussion emphasizes the relationship between gravitational and centripetal forces in determining orbital dynamics. Understanding this equation is crucial for accurately predicting satellite motion.
Bugsy23
Messages
24
Reaction score
0
How do you calculate the orbital period of an object, eg. a satellite, if the only known values are the radius of the orbit and the mass of the central object?
 
Physics news on Phys.org
The equations that come to mind are a = 1/r v2 = wr = 2(pi)r/T and mw2r =Mw2R (the two centripetal forces are equal)...M is the big mass, like the Earth with circular radius orbit R..

if the gravitalional force equals the centripetal...F = ma.. so
GMm/(R+r)2 = mw2r and the small m's drop out...

Then just assume R (radius of orbit of the big central mass) is negligible...
and you are right near the answer...
 
it comes out to be:

T^2= ((2*pi)^2*r^3)/GM

where r is radius and M is mass of central object. T is time period
 
Thread 'Gauss' law seems to imply instantaneous electric field'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Maxwell’s equations imply the following wave equation for the electric field $$\nabla^2\mathbf{E}-\frac{1}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = \frac{1}{\varepsilon_0}\nabla\rho+\mu_0\frac{\partial\mathbf J}{\partial t}.\tag{1}$$ I wonder if eqn.##(1)## can be split into the following transverse part $$\nabla^2\mathbf{E}_T-\frac{1}{c^2}\frac{\partial^2\mathbf{E}_T}{\partial t^2} = \mu_0\frac{\partial\mathbf{J}_T}{\partial t}\tag{2}$$ and longitudinal part...
Back
Top