Calculating satellites´ period of revolution

[JukuJohannes]

Homework Statement

Earths´ satellite orbits 4200km above Earths surface. Count satellites´ trajectory circle-shaped and calculate satellites´period of revolution.

The Attempt at a Solution

I added the Earths´ radius to the 4200 km, which represents the orbiting attitude and then my mind crashed...
please some help

 

[LowlyPion]

Welcome to PF.

What is the acceleration of gravity at that height? (Hint: it's not 9.8)

What other acceleration is there from circular motion?

 

[JukuJohannes]

Welcome to PF.

What is the acceleration of gravity at that height? (Hint: it's not 9.8)

What other acceleration is there from circular motion?

Of course the centripetal-acceleration but I thought that I should know the mass of the satellite to calculate the acceleration of gravity...

btw.. thanks for the welcome

 

[LowlyPion]

Of course the centripetal-acceleration but I thought that I should know the mass of the satellite to calculate the acceleration of gravity...

btw.. thanks for the welcome

Since the 2 accelerations will need to offset to stay in orbit, you won't need the mass.

 

[JukuJohannes]

Since the 2 accelerations will need to offset to stay in orbit, you won't need the mass.

yeah, that settles it down, I think I can see the big picture now,
Thank You!