Question

A spaceship orbiting earth flies to the moon. How is the gravitational force pulling on the spaceship related to the distance that the spaceship is from the earth? As the distance from the earth decreases, the gravitational pull on the spaceship would decrease. The gravitational pull of the earth is constant and therefore the gravitational pull on would not change. There is no gravity on the moon and therefore only the earth will exert gravitational force on the spaceship. As the distance from the earth increases, the gravitational pull on the spaceship would decrease.

Answer 1

The correct answer is "As the distance from the earth increases, the gravitational pull on the spaceship would decrease."

In fact, the gravitational force (attractive) exerted by the Earth on the spaceship is given by
$F=G \frac{Mm}{d^2}$
where G is the gravitational constant, M the Earth's mass, m the mass of the spaceship and d the distance of the spaceship from the Earth. As we can see from the formula, as the distance d between the spaceship and the Earth increases, the gravitational force F decreases, so answer D) is the correct one.