A sphere of mass `40 kg` is attracted by a second sphere of mass `15 kg`, when their centres are `20 cm` apart, with a force of `0.1` miligram weight. Caculate the value of gravitational constant.

Explanation

Here `m_(1)=40 kg,m_(2)=15kg, r=20cm=(20)/(100m)=2xx10^(-1)m`
`F=0.1` milligram weight`=0.1xx10^(-3)`gram weight
`= 10^(-4) xx 10^(-3)` kg wt `= 10^(-7) xx 9.8 N (1kg wt = 9.8N)`
From `F = (Gm_(1)m_(2))/r^(2),`
`G=(Fxxr^(2))/(m_(1)m_(2))=(10^(-7)xx9.8xx(2xx10^(-1))^(2))/(40 xx 15)=6.53xx10^(-11) Nm^(2)//Kg^(2)`