Posted by mac on .
A satellite is in orbit about Earth. Its orbital radius is 7.51×107 m. The mass of the satellite is 5415 kg and the mass of Earth is 5.974×1024 kg. Determine the orbital speed of the satellite in mi/s. 1 mi/s = 1609 m/s.

physics 
tchrwill,
The velocity required to maintain a circular orbit around the Earth may be computed from the following:
Vc = sqrt(µ/r)
where Vc is the circular orbital velocity in feet per second, µ (pronounced meuw as opposed to meow) is the gravitational constant of the Earth, ~3.986365x10^14 ft.^3/sec.^2, and r is the distance from the center of the earth to the altitude in question in feet.
Therefore,
V = sqrt[3.986365x10^14/7.51x10^7] 
physics 
Jane,
I am confused because the answer should be in mi/s.

physics 
tchrwill,
My apologies for the typo.
The velocity required to maintain a circular orbit around the Earth may be computed from the following:
Vc = sqrt(µ/r)
where Vc is the circular orbital velocity in meters per second, µ (pronounced meuw as opposed to meow) is the gravitational constant of the Earth, ~3.986365x10^14 met.^3/sec.^2, and r is the distance from the center of the earth to the altitude in question in meters.
Therefore,
V = sqrt[3.986365x10^14/7.51x10^7]
= 2303.926 met./sec.x3.281ft./met.
= 7559 ft./sec.x1mile/5280ft.
= 1.4316miles/sec.x3600sec./1 hour
= 5154 mi/hr.