2010 AP Calculus AB Free Response #3

Allen Tsao The STEM Coach
30 Oct 201807:27
EducationalLearning
32 Likes 10 Comments

TLDRIn the video, Alan from Bothell Stem Coach tackles AP Calculus AB 2010 Free-Response Question 5, focusing on the non-calculator portion. The problem involves a popular amusement park ride with an initial queue of 700 people. The ride operates for 8 hours, accepting passengers at a rate of 800 people per hour. People arrive at varying rates throughout the day, and Alan uses the concept of the area under the curve to estimate the number of people who arrive between 0 and 3 hours. He discusses the increasing queue size and determines that the line is longest at 3 hours when the arrival rate equals the ride's capacity. Alan also attempts to find the time when the queue disappears by solving an integral expression. However, he makes a mistake by initially forgetting the initial 700 people in the queue, which he later corrects. The video concludes with a reminder that Alan offers free homework help on Twitch and Discord.

Takeaways
  • 🎢 The amusement park ride starts with 700 people in line and operates for 8 hours.
  • ⏰ The ride accepts passengers at a rate of 800 people per hour.
  • 📈 The rate at which people arrive forms a graph where time is measured in hours.
  • 🔢 To find out how many people arrived between 0 and 3 hours, you calculate the area under the graph, which can be approximated as the sum of two trapezoids.
  • 📉 The number of people waiting in line increases between 2 and 3 hours because the arrival rate is higher than the ride's capacity.
  • 🆙 The line for the ride is longest when the arrival rate equals the ride's capacity, which happens at 3 hours.
  • 🧮 The integral from 0 to t of the difference between the arrival rate and 800 people per hour gives the number of people in line at time t.
  • ✅ To find the maximum line length, set the derivative of the integral equal to zero, which occurs when the arrival rate equals 800 people per hour.
  • 🕒 The line is longest at approximately 3 hours into the operation.
  • 🚫 The presenter made a mistake by initially forgetting to include the initial 700 people in the line, which affected subsequent calculations.
  • 🗣️ The presenter offers free homework help on Twitch and Discord for further assistance.
Q & A
  • How many people were initially in line for the amusement park ride?

    -There were initially 700 people in line for the amusement park ride.

  • What is the rate at which the ride accepts passengers per hour?

    -The ride accepts passengers at a rate of 800 people per hour.

  • How many hours does the amusement park operate before closing?

    -The amusement park operates for 8 hours before closing.

  • What is the method used to calculate the number of people who arrived at the ride between zero and three hours?

    -The method used is to calculate the area under the curve graphically, which is divided into two trapezoids.

  • What is the total number of people that arrived at the ride between zero and three hours?

    -The total number of people that arrived at the ride between zero and three hours is 3,200.

  • Is the number of people waiting in line to get on the ride increasing or decreasing between 2 and 3 hours?

    -The number of people waiting in line is increasing between 2 and 3 hours because the rate of people arriving (R of T) is greater than 800 people per hour during that time.

  • At what time is the line for the ride the longest?

    -The line for the ride is the longest at time T equals 3 hours.

  • What is the integral expression used to find the number of people in line at a given time?

    -The integral expression used is the integral from 0 to t of R of T minus 800 dt.

  • What is the earliest time T at which there's no longer a line for the ride?

    -The earliest time T at which there's no longer a line for the ride is when the integral from 0 to t of R of T minus 800 dt equals zero.

  • How many people were on the line at 3 hours?

    -At 3 hours, there were 3,200 people who had arrived minus 2,400 people who got onto the ride, which equals 800 people on the line.

  • What was the mistake made in the calculation of the number of people on the line at 3 hours?

    -The mistake was not including the initial 700 people already in line when the park opened, which should have been added to the final calculation.

  • What additional resources does Alan offer for homework help?

    -Alan offers free homework help on Twitch and Discord.

Outlines
00:00
🎢 Amusement Park Ride Queue Analysis

In this paragraph, Alan from Bothell Stem Coach discusses an AP Calculus problem set in 2010. The problem involves calculating the number of people in line for a popular amusement park ride that starts with 700 people and operates for 8 hours. The rate at which people join the line varies, and the ride can accommodate 800 people per hour. Alan uses the concept of the area under a graph to represent the number of people arriving and leaving the queue. He breaks down the problem into two trapezoids and calculates the area to find out how many people arrived between 0 and 3 hours. He also addresses whether the line is increasing or decreasing and determines the time when the line is the longest. Finally, Alan identifies a mistake in his calculation due to an oversight of the initial 700 people in line and corrects it.

05:02
🧮 Correcting the Queue Calculation Error

This paragraph focuses on correcting the error made in the previous calculation. Alan realizes that he forgot to include the initial 700 people already in line at the start of the ride's operation. He acknowledges the mistake and corrects the calculation by adding 700 to the total number of people who arrived. Alan then discusses the integral expression to find the earliest time when there is no longer a line for the ride, indicating that the solution to this expression gives the time when the number of people in line is zero. He concludes by summarizing the corrected calculations and encourages viewers to engage with the content through comments, likes, or subscriptions. Alan also offers free homework help on Twitch and Discord and signs off, promising to see viewers in the next video.

Mindmap
Keywords
💡AP Calculus AB
AP Calculus AB is a college-level calculus course offered by the College Board as part of the Advanced Placement program. It is designed to introduce students to the study of calculus, which includes concepts such as limits, derivatives, and integrals. In the video, the theme revolves around solving calculus problems related to a real-world scenario involving an amusement park ride.
💡Non-calculator portion
The non-calculator portion of an AP Calculus exam refers to the section of the test where students are expected to solve mathematical problems without the aid of a calculator. This requires a deeper understanding of mathematical concepts and the ability to perform calculations mentally or on paper. In the video, the focus is on solving problems in this manner, highlighting the importance of mathematical intuition and manual calculation skills.
💡Amusement park ride
An amusement park ride is a recreational attraction found in amusement parks, designed to provide entertainment and excitement through physical experiences. In the context of the video, the amusement park ride serves as a backdrop for a calculus problem involving the rate at which people arrive and the capacity at which the ride can accommodate them.
💡Rate
In mathematics and physics, the rate refers to the ratio of the change in a quantity to the change in another quantity, often time. In the video, the rate is used to describe how quickly people are arriving at the amusement park ride and how quickly they are being accepted onto the ride, which is crucial for determining the size of the line and when it will be at its longest.
💡Integral
An integral in calculus is a mathematical concept that represents the area under a curve, which can be used to calculate quantities such as the amount of substance accumulated over time. In the video, the integral is used to find the total number of people who have arrived at the ride over a certain period, which is a key part of solving the problem.
💡Trapezoids
A trapezoid is a quadrilateral with at least one pair of parallel sides. In the context of the video, trapezoids are used to approximate the area under a curve, which represents the number of people arriving at the amusement park ride. This method is part of the technique for solving integrals graphically.
💡Fundamental Theorem of Calculus
The Fundamental Theorem of Calculus is a central theorem that links the concept of the integral to that of the derivative, showing that these two operations are essentially the inverse of each other. In the video, the theorem is mentioned in the context of finding the maximum length of the line for the ride by setting the derivative of the integral equal to zero.
💡Maximum
A maximum is the highest value that a function can attain. In the video, the concept of a maximum is used to determine the time at which the line for the amusement park ride is the longest. This is done by finding when the rate at which people are arriving equals the rate at which they are being accepted onto the ride.
💡Derivative
A derivative in calculus represents the rate at which a quantity changes with respect to another quantity. It is a measure of sensitivity to change. In the video, the derivative is used to find the point at which the line for the ride is at its longest, by setting it equal to zero and solving for time 't'.
💡Area under the curve
The area under a curve, often represented by an integral, is a way to quantify the total amount of a variable when it is changing continuously. In the video, calculating the area under the curve is essential for determining the total number of people who arrived at the amusement park ride within a specific time frame.
💡Graphical method
A graphical method in mathematics refers to the use of visual representations, such as graphs or diagrams, to solve problems. In the context of the video, the graphical method is employed to approximate the area under the curve representing the rate at which people arrive at the amusement park ride, by breaking it down into trapezoids.
Highlights

Alan is discussing AP Calculus AB 2010 exam questions.

The focus is on the non-calculator portion of the exam.

A scenario involving an amusement park ride with 700 people in line is presented.

The rate at which people move on to the ride is 800 people per hour.

The problem involves calculating the number of people who arrive at the ride between 0 and 3 hours.

Alan visualizes the area under the graph representing the rate of people's arrival as two trapezoids.

The area under the curve is calculated graphically without a calculator.

The total number of people who arrived within the first three hours is 3,200.

The line for the ride is longest when the number of people arriving equals the ride's capacity of 800 people per hour.

The maximum line length occurs at T equals 3 hours.

Alan makes a mistake by forgetting to include the initial 700 people in the line, which affects the calculation.

The correct number of people in line at the maximum point should include the initial 700 people.

Alan provides a method to find the earliest time when there's no longer a line for the ride by solving an integral expression.

The final calculation reveals that at 3 hours, 2,424 people have boarded the ride.

Alan offers free homework help on Twitch and Discord for further assistance.

The video concludes with an invitation to engage with the content through comments, likes, or subscriptions.

Transcripts
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