Calculate the period of the Earth's moon if the radius of orbit was twice the actual value of 3.9 x 10^8 m.(adsbygoogle = window.adsbygoogle || []).push({});

a. 1.13 x 10^6 s or 13 days

b. 2.3 x 10^6 s or 26 days

c. 5.14 x 10^6 s or 59 days

d. 6.85 x10^6 s or 79 days

So far I got: v=velocity; T=time; h= hieght from surface

v=?

T=?

h=?

re= 6.38 x 10^6

me= 5.97 x 10^24

G= 6.67 x 10^-11

Another question I have is, if the radius of earth is doubled but the mass remains the same what would happen to the acceleration due to gravity. Would I divide 9.80 by 2, multiply by 2, or multiply by 1/4.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Newton's Variation of Kepler's third law

**Physics Forums | Science Articles, Homework Help, Discussion**