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Chapter 8第8章

Applications of Integration积分的应用

AP-Style Practice QuestionsAP 风格练习题

EASYMEDIUMHARD

Topics主题 8.1 - 8.12AB



Name:姓名:Period:课时:
PART ISections 8.1 - 8.8第 8.1 至 8.8 节

Multiple Choice Questions选择题

Show all supporting work on scratch paper. On the AP Exam, Section I is split into a no-calculator and a calculator-allowed part, each question below is labeled accordingly.请在草稿纸上写出所有解题步骤。AP 考试第一部分分为不允许使用计算器和允许使用计算器两部分,每道题已注明。

Q1EASY8.1 Average Value8.1 平均值No Calculator

The average value of $f(x)=x^{2}$ on $[0,3]$ is$f(x)=x^{2}$ 在 $[0,3]$ 上的平均值为

Q2EASY8.2 Motion (Displacement)8.2 运动(位移)No Calculator

A particle moves along the $x$-axis with velocity $v(t)=t-2$ for $0\le t\le 3$. The displacement of the particle on this interval is一质点沿 $x$ 轴运动,速度为 $v(t)=t-2$,$0\le t\le 3$。该质点在此区间上的位移为

Q3MEDIUM8.2 Total Distance8.2 总路程No Calculator

A particle moves with velocity $v(t)=t-2$ for $0\le t\le 3$. The total distance traveled is一质点的速度为 $v(t)=t-2$,$0\le t\le 3$。该质点走过的总路程为

Q4MEDIUM8.3 Accumulation8.3 累积量Calculator

Water flows into a tank at a rate of $r(t)=4+\sin(t)$ gallons per minute, for $0\le t\le 6$. The tank initially contains $50$ gallons. The amount in the tank at $t=6$ is closest to水以 $r(t)=4+\sin(t)$ 加仑/分钟的速率流入水箱,$0\le t\le 6$。水箱初始容量为 $50$ 加仑。$t=6$ 时水箱中的水量最接近

Q5EASY8.4 Area (in $x$)8.4 面积(以 $x$ 为变量)No Calculator

The area enclosed by $y=x$ and $y=x^{2}$ is$y=x$ 与 $y=x^{2}$ 所围的面积为

Q6MEDIUM8.5 Area (in $y$)8.5 面积(以 $y$ 为变量)No Calculator

Which integral gives the area enclosed by $x=y^{2}$ and $x=y+2$?下列哪个积分表示 $x=y^{2}$ 与 $x=y+2$ 所围的面积?

Q7HARD8.6 Multiple Intersections8.6 多交点面积No Calculator

The total area of the regions enclosed between $y=x^{3}-x$ and the $x$-axis is$y=x^{3}-x$ 与 $x$ 轴所围各区域的总面积为

Q8MEDIUM8.7 Cross Sections (Squares)8.7 截面法(正方形)No Calculator

The base of a solid is the region in the $xy$-plane bounded by $y=x$, $y=0$, and $x=2$. Cross sections perpendicular to the $x$-axis are squares. The volume of the solid is某立体的底面是 $xy$ 平面上由 $y=x$、$y=0$ 和 $x=2$ 所围的区域。垂直于 $x$ 轴的截面为正方形。该立体的体积为

Q9HARD8.8 Cross Sections (Triangles)8.8 截面法(三角形)No Calculator

The base of a solid is the region bounded by $y=\sqrt{x}$ and the $x$-axis on $[0,4]$. Cross sections perpendicular to the $x$-axis are equilateral triangles. The volume is某立体的底面是 $[0,4]$ 上由 $y=\sqrt{x}$ 与 $x$ 轴所围的区域。垂直于 $x$ 轴的截面为等边三角形。该立体的体积为

Q10EASY8.9 Disc Method8.9 圆盘法No Calculator

The region bounded by $y=\sqrt{x}$, $y=0$, and $x=4$ is revolved about the $x$-axis. The volume is由 $y=\sqrt{x}$、$y=0$ 和 $x=4$ 所围的区域绕 $x$ 轴旋转一周。体积为

Q11MEDIUM8.10 Disc (Other Axes)8.10 圆盘法(其他轴)No Calculator

The region bounded by $y=x^{2}$, $y=0$, and $x=2$ is revolved about the line $y=-1$. Which integral gives the volume?由 $y=x^{2}$、$y=0$ 和 $x=2$ 所围的区域绕直线 $y=-1$ 旋转一周。下列哪个积分表示其体积?

Q12HARD8.11 Washer (about $x$-axis)8.11 垫圈法(绕 $x$ 轴)No Calculator

Let $R$ be the region enclosed by $y=x$ and $y=x^{2}$. The volume of the solid formed when $R$ is revolved about the $x$-axis is设 $R$ 为 $y=x$ 与 $y=x^{2}$ 所围的区域。将 $R$ 绕 $x$ 轴旋转一周所得立体的体积为

Q13HARD8.12 Washer (Other Axes)8.12 垫圈法(其他轴)No Calculator

Let $R$ be the region bounded by $y=x^{2}$ and $y=4$. Which integral gives the volume of the solid generated when $R$ is revolved about the line $y=5$?设 $R$ 为 $y=x^{2}$ 与 $y=4$ 所围的区域。下列哪个积分表示将 $R$ 绕直线 $y=5$ 旋转一周所得立体的体积?

Q14MEDIUM8.3 Tabular Accumulation8.3 表格数据累积No Calculator

The rate at which people enter a park is modeled by $E(t)$ people per hour, where $t$ is hours since opening. Selected values:进入公园的人数速率由 $E(t)$(人/小时)建模,其中 $t$ 为开放后的小时数。部分数值如下:

$t$ (hr小时)$0$$2$$4$$6$$8$
$E(t)$$100$$240$$380$$300$$150$

Using a left Riemann sum with the four subintervals of equal length, the approximate total number of people who entered during the $8$ hours is利用四个等长子区间的左黎曼和,在 $8$ 小时内进入公园的总人数近似为

Q15EASY8.1 Average Value8.1 平均值No Calculator

If $f(x)=4x$, the average value of $f$ on $[1,3]$ is若 $f(x)=4x$,则 $f$ 在 $[1,3]$ 上的平均值为

Q16MEDIUM8.2 Position from Velocity8.2 由速度求位置No Calculator

A particle has velocity $v(t)=3t^{2}-6t$ and initial position $x(0)=2$. Then $x(2)=$一质点的速度为 $v(t)=3t^{2}-6t$,初始位置为 $x(0)=2$。则 $x(2)=$

Q17MEDIUM8.4 Area between Curves8.4 曲线间面积No Calculator

The area enclosed by $y=4-x^{2}$ and the $x$-axis is$y=4-x^{2}$ 与 $x$ 轴所围的面积为

Q18HARD8.7 Cross Sections (Semicircles)8.7 截面法(半圆)No Calculator

The base of a solid is the region under $y=\sqrt{x}$ on $[0,4]$. Cross sections perpendicular to the $x$-axis are semicircles with diameter in the base. The volume is某立体的底面是 $[0,4]$ 上 $y=\sqrt{x}$ 下方的区域。垂直于 $x$ 轴的截面为直径在底面上的半圆。体积为

PART IIShow All Work展示完整解题过程

Free-Response Questions自由回答题

Free-response answers must include setup, units, and interpretation in context where appropriate. A calculator is permitted unless marked otherwise.自由回答题须包含解题设置、单位,以及在适当时对结果的情境解释。除非特别注明,否则允许使用计算器。

FRQ 1EASY8.1 / 8.2 Motion8.1 / 8.2 运动No Calculator

A particle moves along the $x$-axis with velocity $v(t)=t^{2}-4t+3$ for $0\le t\le 4$. The particle is at position $x=2$ when $t=0$.一质点沿 $x$ 轴运动,速度为 $v(t)=t^{2}-4t+3$,$0\le t\le 4$。$t=0$ 时质点位于 $x=2$。

(a) Find the displacement of the particle on $[0,4]$.求质点在 $[0,4]$ 上的位移。
(b) Find the position of the particle at $t=4$.求质点在 $t=4$ 时的位置。
(c) Find the average value of the velocity on $[0,4]$.求速度在 $[0,4]$ 上的平均值。
(d) Find the total distance traveled on $[0,4]$.求质点在 $[0,4]$ 上走过的总路程。
FRQ 2MEDIUM8.4 / 8.7 / 8.9 Area & Volume8.4 / 8.7 / 8.9 面积与体积Calculator

Let $R$ be the region in the first quadrant bounded by the graphs of $y=\sin(\pi x)$ and $y=x-x^{2}$.设 $R$ 为第一象限中由 $y=\sin(\pi x)$ 与 $y=x-x^{2}$ 所围的区域。

(a) Find the area of the region $R$.求区域 $R$ 的面积。
(b) Find the volume of the solid generated when $R$ is revolved about the $x$-axis.求将 $R$ 绕 $x$ 轴旋转一周所得立体的体积。
(c) The region $R$ is the base of a solid. For each $x$, the cross section perpendicular to the $x$-axis is a square. Write, but do not evaluate, an integral expression for the volume.区域 $R$ 为某立体的底面。对于每个 $x$,垂直于 $x$ 轴的截面为正方形。写出(但不需计算)体积的积分表达式。
FRQ 3MEDIUM8.3 Accumulation (Applied)8.3 累积量(应用)Calculator

Water is being pumped into a tank at a rate of $P(t)=20+5\sin(t/2)$ gallons per minute. At the same time, water is leaking out at a rate of $L(t)=2+0.5t$ gallons per minute, for $0\le t\le 30$. At time $t=0$, the tank contains $400$ gallons of water.水以 $P(t)=20+5\sin(t/2)$ 加仑/分钟的速率泵入水箱,同时以 $L(t)=2+0.5t$ 加仑/分钟的速率漏出,$0\le t\le 30$。$t=0$ 时水箱中有 $400$ 加仑水。

(a) How many gallons of water are pumped into the tank during the first $30$ minutes? Show the setup for your integral.前 $30$ 分钟内共泵入多少加仑水?请写出积分的设置过程。
(b) Write an expression, involving an integral, for the amount of water in the tank at time $t$, for $0\le t\le 30$.写出 $0\le t\le 30$ 时刻水箱中水量的含积分表达式。
(c) Find the amount of water in the tank at $t=30$. Indicate units of measure.求 $t=30$ 时水箱中的水量,并注明单位。
(d) Is the amount of water in the tank increasing or decreasing at $t=15$? Justify.在 $t=15$ 时,水箱中的水量是增加还是减少?请说明理由。
FRQ 4HARD8.4 / 8.8 / 8.11 / 8.12 Volume Setup8.4 / 8.8 / 8.11 / 8.12 体积设置Calculator

Let $R$ be the region enclosed by the graphs of $y=e^{-x^{2}}$ and $y=\dfrac{1}{2}$.设 $R$ 为 $y=e^{-x^{2}}$ 与 $y=\dfrac{1}{2}$ 所围的区域。

(a) Find the area of $R$.求区域 $R$ 的面积。
(b) Set up, but do not evaluate, an integral expression for the volume of the solid generated when $R$ is revolved about the $x$-axis.建立(但不需计算)将 $R$ 绕 $x$ 轴旋转一周所得立体体积的积分表达式。
(c) Set up, but do not evaluate, an integral expression for the volume of the solid generated when $R$ is revolved about the line $y=-1$.建立(但不需计算)将 $R$ 绕直线 $y=-1$ 旋转一周所得立体体积的积分表达式。
(d) $R$ is the base of a solid whose cross sections perpendicular to the $x$-axis are isosceles right triangles with one leg in the base. Write, but do not evaluate, an integral expression for the volume.$R$ 为某立体的底面,该立体垂直于 $x$ 轴的截面为等腰直角三角形,且一条直角边在底面上。写出(但不需计算)体积的积分表达式。
FRQ 5HARD8.2 / 8.3 Table-Based8.2 / 8.3 表格数据No Calculator

A car travels along a straight road for $12$ seconds. The car's velocity $v(t)$, in meters per second, is differentiable. Selected values are given.一辆汽车沿直路行驶 $12$ 秒。汽车速度 $v(t)$(米/秒)可微,部分数值如下。

$t$ (sec)$0$$3$$6$$9$$12$
$v(t)$ (m/s)$0$$12$$20$$15$$6$
(a) Using a midpoint Riemann sum with two equal subintervals of length $6$, approximate $\displaystyle\int_{0}^{12}v(t)\,dt$. Using correct units, explain the meaning of this integral in context.利用两个长度为 $6$ 的等长子区间的中点黎曼和,近似计算 $\displaystyle\int_{0}^{12}v(t)\,dt$。用正确单位说明该积分在情境中的含义。
(b) Using a trapezoidal sum with the four subintervals shown, approximate $\dfrac{1}{12}\displaystyle\int_{0}^{12}v(t)\,dt$. Using correct units, explain the meaning of this value in context.利用图中四个子区间的梯形和,近似计算 $\dfrac{1}{12}\displaystyle\int_{0}^{12}v(t)\,dt$。用正确单位说明该值在情境中的含义。
(c) Must there exist a time $t$, $3\lt t\lt 9$, at which the acceleration of the car is zero? Justify your answer.在 $3\lt t\lt 9$ 范围内,是否一定存在某时刻汽车加速度为零?请说明理由。
(d) For $0\le t\le 12$, suppose the car's acceleration is $a(t)=v'(t)$. Is the trapezoidal approximation in part (b) an over- or underestimate of the true average velocity if $v$ is concave down on $(0,12)$? Justify.对于 $0\le t\le 12$,设汽车加速度为 $a(t)=v'(t)$。若 $v$ 在 $(0,12)$ 上是凹的,则第 (b) 部分中梯形近似值是真实平均速度的高估还是低估?请说明理由。