Spheres A and B of uniform density have masses 1 kg and 100 kg respectively. Their centres are separated by 100m. (i) Find the gravitational force betweeen them.
`[M_("(earth)")=6xx10^(24)kg, R_("(earth)")=6400km]`

Explanation

Data : `m_(1)=1kg, m_(2)kg, r = 100m,`
`M=6xx10^(24)kg, R = 6400km=6400xx10^(3)m,`
`t=1s, s=1cm=1xx10^(-2)m,`
`G=6.67xx10^(-11)N.m^(2)//kg^(2)`
`F_(1)=?, F_(2)=?, v_(1)=? , t_(1)=?, v_(2)=? , t_(2)=?`
(i) `F_(1)=(Gm_(1)m_(2))/(r^(2))`
`=(6.67xx10^(-11)N.m^(2)//kg^(2)xx1kgxx100kg)/((100m)^(2))`
`=6.67xx10^(-13)N`