PrepTest 102, Section 3, Question 19
When an ordinary piece of steel is put(92 more words not shown)
Which one of the following(5 more words not shown)
- Abecome larger in(7 more words not shown)
- Bflow toward the(10 more words not shown)
- Ccompress, although not(8 more words not shown)
- Ddivide into exactly(16 more words not shown)
- Ebe thinner in(26 more words not shown)
Reading the argument
Picture pressing down on the middle of a sheet while its material slowly moves away from the pressure. Where would that material go? Toward the parts under less pressure.
That is what this passage tells us happens to glass. We do not need outside knowledge about whether glass should be called a fluid. Here, we are given two different responses to pressure: steel loses some volume, while the glass keeps the same volume and changes where that material is located.
What we’re looking for
The heavy object presses on the middle of a sheet that starts with uniform thickness. The glass beneath it slowly flows outward. We need to complete the conclusion, so follow that movement: material leaves the pressed area and moves toward the less-pressed areas. The middle should end up thinner relative to those other parts.
Working the answers
- A
The problem is “still be of uniform thickness.” The pressure is concentrated under the object, and material flows away from that area. We should expect a difference in thickness, not a sheet that stays equally thick everywhere.
Also, be careful not to confuse spreading over a larger surface area with increasing in volume. Something can spread out without containing more material. The passage rules out a volume change; the uneven pressure and resulting flow are what rule out A's claim of continued uniform thickness.
- B
The direction is backward. The passage says the glass flows from the area under sustained pressure toward areas under less pressure. B sends it toward the point of greatest pressure.
- C
Compression is what the passage says happens to steel. It explicitly contrasts that with glass, whose volume remains unchanged as it flows. Saying the glass compresses less than steel still says it compresses, contrary to the given description.
- D
Nothing gives us exactly two pieces, much less their particular sizes and shapes. The setup specifies that the sheet supports the object's weight without cracking, and the described response is slow movement toward lower-pressure areas. Dividing into two pieces is an unsupported result.
- ECorrect
The glass under the object flows toward areas under less pressure. That leaves the pressed portion thinner than the portions not under that pressure. The total volume can stay the same while the material is redistributed. E follows the movement we predicted rather than introducing compression or breakage.
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