# Question #6db4b

Feb 24, 2016

Weight of a man on moon surface will be $\frac{W}{5}$,
where $W$ is his weight on Earth.

#### Explanation:

The weight of a body on any planet is the gravitational force between a planet and a body calculated by the formula
$W = \gamma \cdot \frac{{M}_{b} \cdot {M}_{p}}{R} ^ 2$
where
$\gamma$ is a gravitational constant,
${M}_{b}$ is a mass of a body,
${M}_{p}$ is a mass of a planet,
$R$ is the distance between the center of a planet and a center of a body (which for all intents and purposes should be taken as the radius of a planet)

If we decrease ${M}_{p}$ by a factor of $80$ and decrease $R$ by a factor of $4$, the gravitational force will change by a factor of ${4}^{2} / 80 = \frac{1}{5}$.