Sat practice Test #8 Answer Explanations

Choice C is the best answer. The lower graph, which shows the “tip 
moving away from salt surface,” indicates that when the microscope 
tip was 15 nanometers from the surface, the force on the tip was 
approximately 0.75 micronewtons.
Choices A, B, and D are incorrect because the graph shows that when 
the microscope tip was 15 nanometers from the salt surface, the force 
on the tip was approximately 0.75 micronewtons, not 0 micronewtons 
(choice A), 0.25 micronewtons (choice B), or 1.25 micronewtons 
(choice D).
QUESTION 31
Choice D is the best answer. The bottom graph illustrates the process 
described in the first sentence of the seventh paragraph of the passage: 
“as the microscope pulls away from the salt, the salt stretches.” On the 
graph, the stretching of the salt is represented by the amount of force, 
in micronewtons, exerted on the microscope tip as the tip moves away 
from the salt surface. The graph shows that force was exerted on the 
tip until the tip reached point T at approximately 22 nanometers from 
the salt surface; from point T on, the force was 0 micronewtons. It can 
be inferred that since no force is being exerted after point T, point T is 
the point at which a salt nanowire breaks.
Choices A, B, and C are incorrect because the labels P, Q, and R all 
appear on the top graph, which represents data on the movement of 
the microscope tip toward the salt surface. As the fifth sentence of the 
fifth paragraph explains, when the microscope tip moved toward the 
salt, “the salt actually stretched out to glom on to the microscope 
tip.” Therefore, the first graph shows the salt attaching itself to the 
microscope tip and forming nanowires, not the breaking of a nanowire.
QUESTION 32
Choice B is the best answer. In the first paragraph of Passage 1, 
Douglas argues that throughout the period in which the United States 
had both free and slave states, the nation as a whole “increased from 
four millions to thirty millions of people . . . extended our territory 
from the Mississippi to the Pacific Ocean . . . acquired the Floridas 
and Texas . . . [and had] risen from a weak and feeble power to become 
the terror and admiration of the civilized world.” It can reasonably be 
inferred that Douglas cites such growth in territory and population 
to make the point that the division into free and slave states was 
obviously not a threat to the country’s health or survival.

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Choice A is incorrect because although it can be inferred that Douglas 
would argue for continued expansion of the United States, he cites 
the expansion it has already undergone as support for perpetuating 
the division into free and slave states. Choice C is incorrect because 
although Douglas implies that basic facts pertaining to the historical 
growth of the nation cast doubt on Lincoln’s political agenda, he 
doesn’t imply that Lincoln is unaware of those facts. Choice D is 
incorrect because although Douglas notes that the United States is 
globally perceived to be powerful, he doesn’t imply that this perception 
can be accounted for by the nation’s record of growth.
QUESTION 33