Answer
a) to find the acceleration due to gravity of sun
[tex]g = \dfrac{GM}{R^2}[/tex]
m is mass of sun = 2 x 10³⁰ Kg
R is the radius = 700,000 km = 7 x 10⁷ m
[tex]g = \dfrac{6.67\times 10^{-11}\times 2 \times 10^{30}}{(7\times 10^7)^2}[/tex]
g = 272.24 m/s²
b) mass of the man = 90 Kg
acceleration = 25 g
[tex]F_{net} = m (g_{sun} - 25 g)[/tex]
[tex]F_{net} = 90\times (272.24 - 25\times 10)[/tex]
[tex]F_{net} =2001.6\ N[/tex]
reading of scale on sun
[tex]m' = \dfrac{F_{net}}{g_{sun}}[/tex]
[tex]m' = \dfrac{2001.6}{272.24}[/tex]
m' = 7.35 Kg