2015 年 1 月 24 日 SAT2 真题预测物 理部分：
1. A boy throws a ball straight up in the air and then catches it again. Which of the above graphs best represents the ball ’ s position with respect to time?
Explanation
You can usually answer classification questions a bit more quickly than the standard five-choice completion questions, since you only need to review one set of answer choices to answer a series of questions.
The answer to the question is B. The ball’s position with respect to time can be expressed by the equation y = –1/2 gt2, where g is the downward, acceleration due to gravity. As we can see, the graph of y against t is an upside-down parabola. In more intuitive terms, we know that, over time, a ball thrown in the air will rise, slow down, stop, and then descend.
2. A gas in a closed container is steadily heated over a period of time. Which of the following statements is true of this process?
(A) The average kinetic energy of the gas molecules decreases
(B) The mass of the container increases
(C) The pressure exerted by the gas on the walls of the container increases
(D) The gas changes phase into a liquid
(E) The specific heat of the gas decreases
Explanation
The answer to this question is C. The key lies in remembering the ideal gas law: PV = nRT.
According to this formula, an increase in temperature is accompanied by an increase in pressure. A is wrong, since the average kinetic energy of gas molecules corresponds to their temperature: if the temperature increases, so does the average kinetic energy of the molecules. B is wrong because we’re dealing with a closed container: the mass cannot either increase or decrease. D is wrong because a gas must be cooled, not heated, to change phase into a liquid. Finally, E is wrong because the specific heat of any substance is a coonstant, and not subject to change. We’ll touch on all this and more in Chapter 9: Thermal Physics.
SAT2 考试答题技巧：
1、各人必要记得的第一个SAT2数学测验本领便是，SAT2数学测验并不必要记着数学公式，平凡的数学公式会在考卷上提供应考生，但是考生必要本身思量应该用谁人公式来解题。固然要是考生本身记得一些比力常用的数学公式，可以资助各人更快，更有用率的解答标题。
2、任何测验都必要考生认真读题，对付SAT2数学测验更是云云，由于SAT2数学测验的难度相对不是很大，但是对付速率的要求就很高，考生要是对付标题的要求不熟习，非常有大概做错。
3、SAT2数学测验中，各人肯定要记得，对付有些考题，绘图可以资助考生解题，不要鄙吝本身的笔，只想在头脑中想象，这是不实际的。
4、SAT2数学测验中，各人肯定要知道的SAT2数学测验本领便是，考生可以把测验问卷看成厕纸来用，由于考生在测验问卷上写得任何工具都是不记分的。
5、在SAT2数学测验中，是容许用盘算器的，以是考生要做的便是思量好怎么应该运用本身的盘算器，什么时间用本身的盘算器。
6、SAT2数学测验中，选择题比力多，以是各人在做选择题的时间，应该先看看每个选择的答案，然后再选出你的答案，有的时间，代入法黑白常有用的SAT2数学测验本领。
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