Page 28 - Force 10

Derivation part

Let us consider two objects A and B having masses M and M respectively are
2
1
separated by a distance d. If the force of attraction between is F, then according

to the law of gravitation,

i) F ∝ (M x M ……...(i) ( when d is kept constant)
2
1
1
ii) F ∝ ( ) …………...(ii) (when m is kept constant)

2
Combining equation (i) and (ii), we get

× 2
1
F ∝ ( ) ………………………………………..(ii)
2

× 2
1
or, F= G ( ) ,
2

Where ‘ G’ is proportionality constant called Universal gravitational constant. It’s

2
2
Value is 6.67 x 10 -11 Nm /Kg .

Hence, F = G ×