The gravitational attraction A between two masses varies inversely as the square of the distance between them. The force of attraction is 4 lb when the masses are 3 ft apart, what is the attraction when the masses are 6 ft
Apart?
A) 3 lb
B) 1 lb
C) 2 lb
D) 4 lb

Question

Quizplus · Accepted Answer

The gravitational force between two masses is given by the formula $F = G \frac{m_1 m_2}{r^2}$, where $F$ is the force of attraction, $G$ is the gravitational constant, $m_1$ and $m_2$ are the masses, and $r$ is the distance between the centers of the two masses. Since the force varies inversely as the square of the distance, when the distance is doubled (from 3 ft to 6 ft), the force is reduced by a factor of $2^2 = 4$. Therefore, the new force of attraction is $4 lb / 4 = 1 lb$.

The Gravitational Attraction a Between Two Masses Varies Inversely as the Square