# Find the orbital period

## Homework Statement

If a satellite is to orbit Earth at an altitude of 1.00x10^3 Km, what would be its orbital period? rs = 1.00x10^3 km, Mearth = 5.97x10^24 kg, Gravitational Constant = 6.67x10^-11

T= 2∏√r^3/GM

## The Attempt at a Solution

rs = 0.815484549m (i converted the satellite's altitude to meters) T= 2∏√0.815484549^3/6.67x10^-11 x 5.97x10^24 = error in my calculator ):

Edit: i did not convert km into meters correctly so it would be 1 meter

2∏√1^3/6.67x10^-11 x 5.97x10^24

Last edited:

## Answers and Replies

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gneill
Mentor

## Homework Statement

If a satellite is to orbit Earth at an altitude of 1.00x10^3 Km, what would be its orbital period? rs = 1.00x10^3 km, Mearth = 5.97x10^24 kg, Gravitational Constant = 6.67x10^-11

T= 2∏√r^3/GM

## The Attempt at a Solution

rs = 0.815484549m (i converted the satellite's altitude to meters) T= 2∏√0.815484549^3/6.67x10^-11 x 5.97x10^24 = error in my calculator ):
Where does "0.815484549" come from? Also, keep in mind that altitude is not the same thing as radius

Where does "0.815484549" come from? Also, keep in mind that altitude is not the same thing as radius
In my class i have to convert Km to meters so i divide it by 100. So to find the radius of the satellite do i have to add the radius of the earth to the altitude of the satellite?

Thanks

EDIT: I mean 1000 so it would be 1m oops

D H
Staff Emeritus
Think! 1 kilometer is 1000 meters, not 0.01 meters. Aside: How did you get 0.815484549 meters by dividing 1.00x10^3 km by 100? (And once again, you do not want to divide by 100.)

Altitude means height above the surface of the Earth, so to get the distance from the center of the Earth you need to add the Earth's radius to the altitude.

1 person
gneill
Mentor
In my class i have to convert Km to meters so i divide it by 100. So to find the radius of the satellite do i have to add the radius of the earth to the altitude of the satellite?

Thanks

EDIT: I mean 1000 so it would be 1m oops
Each km is 1000 meters. So to convert km to meters, multiply by 1000. Thus, 1000 km is 1000 x 1000 meters. And yes, add the Earth radius to the altitude to determine the orbital radius.

1 person
Think! 1 kilometer is 1000 meters, not 0.01 meters. Aside: How did you get 0.815484549 meters by dividing 1.00x10^3 km by 100? (And once again, you do not want to divide by 100.)

Altitude means height above the surface of the Earth, so to get the distance from the center of the Earth you need to add the Earth's radius to the altitude.
when i divided km by 100 i was thinking cm into meters (because 100cm = 1m ) and yes i got 0.815484549m by doing 1.00x10^3 km by 100, it was pretty stupid of me and thanks for your help