Question

explain gravitational force by giving suitable example

Answer 1

force of gravity or gravitational force is the pulling force experienced by a body from another body. every body in this space has its own gravitational pull. we can say it like every body experience and emits the force from and on the other body respectively. newton gave universal gravitational law according to which universal gravitational constant is 6.67408 x 10⁻¹¹ m³ kg⁻¹ s⁻². 
for example, anything on the earth is pulled down by its gravity. 

Answer 2

in the universe all massive body have nature to attract each other .
this attraction we find out by using of Newton ' s law of gravitation.
according to this law,
gravitational force is directly proportional to product of mass of bodies .e.g
if m and M are two massive body given then ,
Fg directly proportional to Mm
also gravitational force is inversely proportional to squre of separation between them .
e.g Fg inversely proportional to r^2
where r is the separation between M and m .
now,
Fg =K mM/r^2

here K is proportionality constant
named as gravitational constant
hence,
K =G

now,
F =GMm/r^2 .

example :-
best example of this is our solar system , in solar system all satellite astroid, etc are attract to each other , this is reason why they held and move in orbital .