19. scientists estimate that the moon moves away from earth about 3.8 cm per year. how will this change…

19. scientists estimate that the moon moves away from earth about 3.8 cm per year. how will this change affect the force of gravity on the moon by earth? the force of gravity increases because the distance between earth and the moon increases. the force of gravity increases because the distance between earth and the moon decreases. the force of gravity decreases because the distance between earth and the moon increases. the force of gravity decreases because the distance between earth and the moon decreases. clear all

19. scientists estimate that the moon moves away from earth about 3.8 cm per year. how will this change affect the force of gravity on the moon by earth? the force of gravity increases because the distance between earth and the moon increases. the force of gravity increases because the distance between earth and the moon decreases. the force of gravity decreases because the distance between earth and the moon increases. the force of gravity decreases because the distance between earth and the moon decreases. clear all

Answer

Explanation:

Step1: Recall gravitational - force formula

The gravitational - force formula is $F = G\frac{Mm}{r^{2}}$, where $F$ is the gravitational force, $G$ is the gravitational constant, $M$ and $m$ are the masses of the two objects (Earth and Moon in this case), and $r$ is the distance between their centers of mass.

Step2: Analyze the effect of distance change

As the Moon moves away from Earth, $r$ increases. Since $F = G\frac{Mm}{r^{2}}$, when $r$ increases, the value of $\frac{1}{r^{2}}$ decreases. And because $G$, $M$, and $m$ are constant, the gravitational force $F$ decreases.

Answer:

The force of gravity decreases because the distance between Earth and the Moon increases.