A scale from which a rock is suspended reads 5 N when the rock is out of water and 3 N when the rock is submerged. The density of the rock is
A) 1.5 times the density of water.
B) the density of water.
C) 3.5 times the density of water.
D) 2.5 times the density of water.

Question

Quizplus · Accepted Answer

The buoyant force is 2 N (5 N - 3 N), which equals the weight of the water displaced. The weight of the rock is 5 N. The density of the rock is the weight of the rock divided by the buoyant force, which is 5 N / 2 N = 2.5 times the density of water.

A Scale from Which a Rock Is Suspended Reads 5