Two point masses m and M are separated by a distance d. If the separation d remains fixed and the masses are increased to the values 3m and 3M respectively, how does the gravitational force between them change?
A)The force will be one-third as great.
B)The force will be one-ninth as great.
C)The force will be three times as great.
D)The force will be nine times as great.
E)It is impossible to determine without knowing the numerical values of m, M, and d.

Question

Quizplus · Accepted Answer

According to the law of gravitation, the force is directly proportional to the product of masses and inversely proportional to the square of the distance between them. So, when the masses are increased to 3m and 3M, the force becomes (3m) x (3M) x G / d^2, where G is the gravitational constant. This can be simplified as 9(m x M x G / d^2), which is nine times the original force. Therefore, the correct answer is D.

Two Point Masses M and M Are Separated by a Distance