Satellite a has an orbital radius 3.00 times greater than that of satellite b. satellite b's orbital period around earth is 120 minutes. what is satellite a's orbital period?

To find the circumference (orbit) of an object, you use Pi x Diameter. 
As you have the circumference of B, you divide it by Pi to get the Diameter. 
So 120 divided by 3.141592654 = 38.2 minutes for the Diameter. 

As' radius and Diameter will be 3x greater than B. 
38.2 x 3 = 114.6 
To get back to the orbital period, times 114.6 by Pi, and you will get 360 minutes. 

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.