Question

Compare the mutual gravitational force between::

a) You and another person with mass of 100 kg located 2 m from you

b) You and Mars at opposition ( This is when the Sun and Mars are on opposite sides of the

Earth which is also when Mars is closest to Earth in their orbits.)

Answer 1

(a) Suppose my mass = m1 = 65 kg

Now mass of other person = m2 = 100 kg.

Now, Gravitational force between two bodies, m1 and m2 is defined as –

F = Gm1m2/D^2

Where, G = 6.67 x 10^11 Nm^2kg^-2
and, D is the distance between them.

So, F = (6.67 x 10^-11x65x100) / 2^2 = 1.084 x 10^-7 N

(b) Mass of mars = m2 = 6.39x10^23 Kg.

Distance between earth and mars, D = 5.45x10^10 m

Now putting these values in the above expression –

F = (6.67 x 10^-11x65x6.39x10^23) /( 5.45x10^10)^2 = 93.27 x 10^-8 N