Physics Questions: Changes in Gravitational Force and Orbital Speed

[roymartin777]

If the distance between the Earth and the Moon were tripled and the mass of the Earth was tripled, what would happen to the gravitational force between them?

a)Remains the same
b)Increase by a factor of 3
c)Increase by a factor of 9
d)Decrease by a factor of 3
e)Decrease by a factor of 6

The booster motors on a satellite were used to increase its separation from the surface of the Earth by a factor of two. What happens to its orbital speed?

Remains the same
Increases by a factor of two
Increases by a factor of sqrt(2)
Decreases by a factor of sqrt(2)
Decreases by a factor of two
None of the above

I did most questions and just left out these two. hope someone can help me out. thanks. please explain the reason.

 

[fzero]

Do you know Newton's law for gravitational force? The 2nd problem requires a formula for the orbital speed based on the centripetal force law. Check your notes for those and if you're still having problems, post back and show some work.