Question

A sphere of mass 40kg is attracted by another sphere of mass 80kg by a force of 2.5×10^-6N, when their centres are 30mm apart. Find the value of G.

Answer 1

Answer:

We know that gravitational force between two bodies is given by -

F = G m1m2/r²
where m1,m2 are masses of the bodies 
G is Universal gravitation constant.
r is the distance between two objects from their centers.

So here 
F = 2.5 × 10^-6
r = 30mm or 30 × 10^-3 m 
m1 = 40kg
m2 = 80kg 
we have to find the value of G

so plug the values in the formula 

we get 
2.5×10^-6 = G × 80×40/3×10-²

so we get G = 0.0023.. × 10^-8