Given that radius of orbit of earth and Mars is $\displaystyle 1.5\times10^{11}$m and $\displaystyle 2.3\times10^11$m respectively . [1 year=$\displaystyle 3.2\times10^7$ s , radius of sun =$\displaystyle 7.0\times10^8$ , mass of helium atom=$\displaystyle 6.6\times10^{-27}$ kg ]

Determine

(1) Period of revolution of Mars

I found this to be 1.9 year .

(2) Mass of sun

i am not sure bout this

(3) Escape velocity of helium atom from the surface of the sun

i tried using this formula

$\displaystyle v=\sqrt{\frac{2GM}{r}}$

Where M is the mass of sun and r is the radius of sun and of course G is the gravitation constant .