Question

Determien the mass of the Sun using the known value for the period of the Earth and its distance from the Sun.

I do not remeber how to do this

F = ma = Fg = GmM/r^2

Period of earth 3.16 E 7 s
radius earth to moon = 1.5 E 11 m

Answer 1

set that equation equal to centripetal force mV^2/r

and of course V=2PI r/T
so GmM/r^2=m(2PI)^2r/T
then solve for period T.

Answer 2

In your case, insert the period T in seconds and solve for the mass of the sun, M, since that is what was asked for.