Planet X of mass m1 orbits a Sun in uniform circular motion at a distance r1 and speed v1. The mass of the Sun is MS1 and its radius is RS1 as shown in the figure below.

Question

anonymous · Answer

If the planet's mass were doubled, how would its speed v1 change?
1) v1 would remain the same
2) v1 would increase by a factor of the square root of 2
3) v1 would increase by a factor of 2

I think it is 2 because $$a=\frac{ v^2 }{ r }$$

anonymous · Answer

F=ma

$$F=G \frac{ M1M2 }{ r^2 }$$

anonymous · Answer

@satellite73 @Shadowys 

I think I have it right but I just want to make certain.

anonymous · Answer

Yup. It's 2.