# Homework Help: Need some help getting started

1. May 3, 2005

### bullroar_86

Would you agree with the calculation reagarding the speed of an artificial satelite, v = 3 x 10^4 m/s, assuming that it is travelling at an altitude h = 230 km above the earths surface where g = 9.0 m/s^2. ?

The radius of the earth is 6370 km.

Also, how long would it take for the satelite to complete one revolution?

not sure where to start here.. any help would be great

2. May 3, 2005

### arildno

Which force must provide the satelite's centripetal acceleration, and how does that force look like in the case where you are 230 km above the Earth's surface?

3. May 3, 2005

### dextercioby

U can find its KE,but u still would have to know its mass in order to determine its speed (the modulus of its tangential velocity).

If u know the velocity & assume the trajectory is a circle whose radius u already know,then u can easily find the period,wouldn't u say...?

Daniel.

EDIT:Arildno's approach is the right one.You needn't the mass in this case...