The Moon (mass $7.35 \times 10^{22} \mathrm{~kg}$ ) is orbiting about the Earth (mass $5.98 \times 10^{24} \mathrm{~kg}$ ) at a radius of $3.85 \times 10^{8}$ meters. The magnitude of the force of gravity on the Moon due to the Earth is $\left(G=6.67 \times 10^{-11} \mathrm{~N} \mathrm{~m}^{2} / \mathrm{kg}^{2}\right)$
A) $4.10 \times 1012 \mathrm{~N}$.
B) $1.98 \times 1020 \mathrm{~N}$.
C) $9.20 \times 1030 \mathrm{~N}$.
D) $6.70 \times 1024 \mathrm{~N}$.
E) $3.20 \times 10^{28} \mathrm{~N}$.

Question

Quizplus · Accepted Answer

The gravitational force between two masses is given by Newton's law of universal gravitation: $F = G \frac{m_1 m_2}{r^2}$, where $F$ is the gravitational force, $G$ is the gravitational constant ($6.67 \times 10^{-11} \mathrm{~N} \mathrm{~m}^{2} / \mathrm{kg}^{2}$), $m_1$ and $m_2$ are the masses of the two objects, and $r$ is the distance between their centers. Plugging in the given values: $F = 6.67 \times 10^{-11} \frac{(7.35 \times 10^{22})(5.98 \times 10^{24})}{(3.85 \times 10^{8})^2}$, we find that $F$ is approximately $1.98 \times 10^{20} \mathrm{~N}$.

The Moon (Mass 7.35×1022 kg7.35 \times 10^{22} \mathrm{~kg}7.35×1022 kg ) Is Orbiting About the Earth (Mass

The Moon (Mass $7.35 \times 10^{22} \mathrm{~kg}$ ) Is Orbiting About the Earth (Mass