A B  C A L C U L U S
Chapter 8

Applications of Integration

AP-Style Practice Questions

EASYMEDIUMHARD

Topics 8.1 – 8.12AB



Name:Period:
PART ISections 8.1 – 8.8

Multiple Choice Questions

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.

Q1EASY8.1 Average ValueNo Calculator

The average value of $f(x)=x^{2}$ on $[0,3]$ is

Q2EASY8.2 Motion (Displacement)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

Q3MEDIUM8.2 Total DistanceNo Calculator

A particle moves with velocity $v(t)=t-2$ for $0\le t\le 3$. The total distance traveled is

Q4MEDIUM8.3 AccumulationCalculator

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

Q5EASY8.4 Area (in $x$)No Calculator

The area enclosed by $y=x$ and $y=x^{2}$ is

Q6MEDIUM8.5 Area (in $y$)No Calculator

Which integral gives the area enclosed by $x=y^{2}$ and $x=y+2$?

Q7HARD8.6 Multiple IntersectionsNo Calculator

The total area of the regions enclosed between $y=x^{3}-x$ and the $x$-axis is

Q8MEDIUM8.7 Cross Sections (Squares)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

Q9HARD8.8 Cross Sections (Triangles)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

Q10EASY8.9 Disc MethodNo Calculator

The region bounded by $y=\sqrt{x}$, $y=0$, and $x=4$ is revolved about the $x$-axis. The volume is

Q11MEDIUM8.10 Disc (Other Axes)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?

Q12HARD8.11 Washer (about $x$-axis)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

Q13HARD8.12 Washer (Other Axes)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 $y=5$?

Q14MEDIUM8.3 Tabular AccumulationNo 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:

$t$ (hr)$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

Q15EASY8.1 Average ValueNo Calculator

If $f(x)=4x$, the average value of $f$ on $[1,3]$ is

Q16MEDIUM8.2 Position from VelocityNo Calculator

A particle has velocity $v(t)=3t^{2}-6t$ and initial position $x(0)=2$. Then $x(2)=$

Q17MEDIUM8.4 Area between CurvesNo Calculator

The area enclosed by $y=4-x^{2}$ and the $x$-axis is

Q18HARD8.7 Cross Sections (Semicircles)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

PART IIShow All Work

Free-Response Questions

Free-response answers must include setup, units, and interpretation in context where appropriate. A calculator is permitted unless marked otherwise.

FRQ 1EASY8.1 / 8.2 MotionNo 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 $t=0$.

(a) Find the displacement of the particle on $[0,4]$.
(b) Find the position of the particle at $t=4$.
(c) Find the average value of the velocity on $[0,4]$.
(d) Find the total distance traveled on $[0,4]$.
FRQ 2MEDIUM8.4 / 8.7 / 8.9 Area & VolumeCalculator

Let $R$ be the region in the first quadrant bounded by the graphs of $y=\sin(\pi x)$ and $y=x-x^{2}$.

(a) Find the area of the region $R$.
(b) Find the volume of the solid generated when $R$ is revolved about the $x$-axis.
(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.
FRQ 3MEDIUM8.3 Accumulation (Applied)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.

(a) How many gallons of water are pumped into the tank during the first $30$ minutes? Show the setup for your integral.
(b) Write an expression, involving an integral, for the amount of water in the tank at time $t$, for $0\le t\le 30$.
(c) Find the amount of water in the tank at $t=30$. Indicate units of measure.
(d) Is the amount of water in the tank increasing or decreasing at $t=15$? Justify.
FRQ 4HARD8.4 / 8.8 / 8.11 / 8.12 Volume SetupCalculator

Let $R$ be the region enclosed by the graphs of $y=e^{-x^{2}}$ and $y=\dfrac{1}{2}$.

(a) Find the area of $R$.
(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.
(c) Set up, but do not evaluate, an integral expression for the volume of the solid generated when $R$ is revolved about the line $y=-1$.
(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.
FRQ 5HARD8.2 / 8.3 Table-BasedNo 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.

$t$ (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.
(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.
(c) Must there exist a time $t$, $3\lt t\lt 9$, at which the acceleration of the car is zero? Justify your answer.
(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.