Solve the problem.
-The gravitational attraction between two masses varies inversely as the square of the distance between them. If the force of attraction is 9 lb when the masses are 2 ft apart, what is the attraction when the masses are 6 ft
Apart?
A) 3 lb
B) 1 lb
C) 4 lb
D) 2 lb

Question

Quizplus · Accepted Answer

Let F be the force and d be the distance between the two masses. According to the problem, we have:

F ∝ 1/d^2

Using the given information, we can set up a proportion:

9 lb ∝ 1/2^2     and      F ∝ 1/6^2

Simplifying both sides, we get:

9 lb ∝ 1/4     and       F ∝ 1/36

Now we can set up another proportion to find F:

9 lb / (1/4) = F / (1/36)

Simplifying, we get:

F = (9 lb / (1/4)) * (1/36) = 1 lb

Therefore, the attraction between the masses when they are 6 ft apart is 1 lb, which corresponds to choice B.

Solve the Problem. -The Gravitational Attraction Between Two Masses Varies Inversely as the Inversely