A planet suitable for human habitation was discovered in outer space, named Beta Star. As we all know, the mass of this planet is twice that of the earth. The information is shown in the figure below.

( 1)5

GM m/R 2 = mg

Mr GM Bei Bei 2 = mg'

G: g' = m ground r bay 2: m bay r ground 2 = 2: 1.

g'=5

(2)600×0.5 = 300 Newton

(3)6× 10^8km

GM day m/r 2 = m v 2/r

Namely: v= root number GM days /R

And because: t = 2π r/v.

So: t1:t2 =1:8 = r1v2: r2v1,and substitute V = V = root number GM day /R as follows:

R 1^3:R2^3= 1:64

So: R 1:R2= 1:4.