Question

A sphere of mass $50kg$ is attached by a second sphere of mass $90kg$ with a force equal to a weight of $0.5mg$ and their centres are $20cm$ apart. The gravitational constant is.

• A. $4.2\times {10}^{-11}N{m}^{2}k{g}^2$
• B. $6.23\times {10}^{-15}N{m}^{2}k{g}^2$
• C. $3.3\times {10}^{-11}N{m}^{2}k{g}^2$
• D. $4.4\times {10}^{-11}N{m}^{2}k{g}^2$

Answer 1

Answer: (D)

$4.4\times {10}^{-11}N{m}^{2}k{g}^2$

$F=\frac{G{m}_1{m}_2}{r^2}$

$F=0.5\times {10}^{-6}\left(9.8\right)N$

$.5\times {10}^{-6}\left(9.8\right)=\frac{G\left(50\right)\left(90\right)}{\left({0.2}^2\right)}$

$⟹G=4.4\times {10}^{-11}N{m}^{2}k{g}^2$