This problem makes use of Newtons Universal Gravitation Formula (F = (G.m1.m2)/(r^2))
In an experiment, using Cavendish's Apparatus(whatever this is!!!) to measure G, the mass of each small sphere is 1,0 kg and the mass of each bigger sphere is 5,0 kg.
The distance between the midpoints of the smaller spheres and the midpoints of the bigger spheres is 80 millimetres. (From the edges of the horizontal beam)
A force of 10^-7 Newton is noted.
Calculate G, with the mass of the beam excluded.
I have no idea what this Cavendish Apparatus is, so i cant imagine what this thing looks like or how it works.