# Homework Help: Speed of satellite in circular orbit

1. Sep 15, 2007

### thatgirlyouknow

1. The problem statement, all variables and given/known data

A satellite is in a circular orbit about the earth (M = 5.98 x 1024 kg). The period of the satellite is 9.93 x 104 s. What is the speed at which the satellite travels?

2. Relevant equations

v=(2*pi*r)/T

v=sqrt((GMe)/r)

3. The attempt at a solution

sqrt[((6.67x10^-11)*(5.98x10^24))/r) = 2*pi*r / T
T = 2piR^3/2 / (sqrt[GMe])
r = 8.414 x 10^15
v = 2*pi*r / t
v = 5.324 x 10^11 m/s

2. Sep 15, 2007

### learningphysics

your formula looks right but I think r is wrong... check your calculations

3. Sep 15, 2007

### thatgirlyouknow

Ok after reworking I got that r = 46357704 m. So:

v = sqrt[(GMe)/r]
v = sqrt[(6.67x10^-11*5.98x10^24)/(46357704)]
v = 3594.51 m/s

But this still isn't right. Are my calculations wrong at some point?

4. Sep 15, 2007

### thatgirlyouknow

Ok I worked it again and got v = 2933.27 m/s. (Hooray human error). Can anyone verify that as correct?

5. Sep 15, 2007

### learningphysics

yes, looks right to me.