# Satelite in EQUATORIAL orbit

1. Dec 3, 2009

### cortozld

1. The problem statement, all variables and given/known data
An earth's satelite is in equatorial orbit at 352,000 km above earth. What is the orbital velocity (m/s) of the satelite (4 sig figs)

2. Relevant equations
g1d1^2=g2d2^2 to find gravity at the height of the satellite

3. The attempt at a solution
I don't really know what an equatorial orbit is, i tried solving it as if it was a circular orbit but that didn't work. My guess was that equatorial means it goes around earth once per year, but no idea...

2. Dec 3, 2009

### mgb_phys

Equatorial orbit just means one above the equator.
The equation you are looking for is Kepler's third law - it will give you the period of the orbit.
Then from the distance you can work out the circumference and so the speed.

hint - you are given an altitude but the orbit depends on the radius, from the centre of the earth

3. Dec 3, 2009

### cortozld

so kepler's 3rd law is T1^2=R1^3
T2^2 R2^3

so T2 is the period, R1 is radius of earth, and R2 is radius of my orbit? what is T1 then?

4. Dec 3, 2009

### mgb_phys

Kepler's law is T^2 $$\propto$$ r^3

You should be able to find an equation in your text book or on wikipedia involving G and the Earth's mass

5. Dec 3, 2009

### cortozld

so my equation will be T^2$$\propto$$ 358370000^3? im getting a really low answer and according to my teacher it is wrong