Posted by **tom** on Wednesday, November 24, 2010 at 2:08pm.

A satellite of mass 210 kg is launched from a site on Earth's equator into an orbit at 210 km above the surface of Earth.

(a) Assuming a circular orbit, what is the orbital period of this satellite?

(b) What is the satellite's speed in its orbit?

(c) What is the minimum energy necessary to place the satellite in orbit, assuming no air friction?

J

- Physics -
**drwls**, Wednesday, November 24, 2010 at 2:20pm
For (a) and (b), the satellite mass will not matter. The orbit distance from the center of the earth is R = 6378 + 210 = 6588 km. Speed is

V = 2 pi R/P

where P is the period.

Get the period from

G M/R^2 = V^2/R

G M = V^2*R = 4 pi^2 R^3/P^2

Solve for P

M is the earth's mass

Energy required = (1/2) m V^2 + GMm[1/Re - (1/(Re + 211,000m)]

m is the satellite mass

There is a small additional term (+ or - that takes into account the rotational speed of the earth at the launch point. That gives the rocket launcher a bit of a boost, especially at the equator.

- Physics -
**derp**, Tuesday, November 6, 2012 at 10:00pm
I need a better explanation than that, and an answer to show you are right. thanks

## Answer This Question

## Related Questions

- physics - A satellite of mass 205 kg is launched from a site on Earth's equator ...
- Physics - A satellite of mass 220 kg is launched from a site on Earth's equator ...
- physics - A satellite of mass 225 kg is launched from a site on Earth's equator...
- physics - Estimate the energy required from fuel to launch a 1465 kg satellite ...
- Physics help PLZ!! - Estimate the energy required from fuel to launch a 1465 kg ...
- physics - A spy satellite was launched into a circular orbit with a height of ...
- Physics - Some communication satellites are put into a circular geosynchronous ...
- physics - Two Earth satellites, A and B, each of mass m, are to be launched into...
- physics - Two Earth satellites, A and B, each of mass m, are to be launched into...
- Physics - A communications satellite with a mass of 450 kg is in a circular ...

More Related Questions