Question

If a man weighed 85kg, how much gravitational force do the three (Castor, Pollux, Alhena) brightest stars of gemini exert on that man?

Answer 1

Given:

Weight of man = 85kg

Stars = 3

To Find:

Force of the brightest star.

Solution:

The basic info about three stars is -

Alhena -

mass = 5.59 x 10`30 kg

distance to earth = 1.05 x 10`18 m

Pollux -

mass = 4.057 x 10`30 kg

distance to earth = 3.19 x 10`17 m

Castor -

mass = 4.37 x 10`30 kg

distance to earth = 4.81 x 10`17 m

Now,

FG = gm1m2/r²

Thus -

Between pollux and man -

6.67`10 × 85 × 4.057 x 10`30 kg/ 3.19 x 10`17 m

= 2.26 x 10`13

Between castor and man -

6.67`10 × 85 × 4.37 x 10`30 kg/ 4.81 x 10`17 m

= 1.07 x 10`13

Between alhena and man -

6.67`10 × 85 ×5.59 x 10`30 kg/ 1.05 x 10`18

= 2.87 x 10` 14

Answer : The gravitational force of three stars is - 2.26 x 10`13 N, 1.07 x 10`13N, 2.87 x 10` 14 N