/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 9 Making up a story about a car tr... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Making up a story about a car trip: You begin from home on a car trip. Initially your velocity is a small positive number. Shortly after you leave, velocity decreases momentarily to zero. Then it increases rapidly to a large positive number and remains constant for this part of the trip. After a time, velocity decreases to zero and then changes to a large negative number. a. Make a graph of velocity for this trip. b. Discuss your distance from home during this driving event, and make a graph. c. Make up a driving story that matches this description.

Short Answer

Expert verified
Graph: Start slow, stop, speed up fast, stop, then reverse. Distance: Increases, constant, increases faster, constant, decreases. Story: Morning trip starting slow, freeway speed, stop in traffic, quick return home.

Step by step solution

01

Understanding the problem

You start with a small positive velocity, implying you are moving away from home. The velocity decreases, indicating a stop. Then it increases to a larger positive value, showing faster movement away from home. Finally, the velocity decreases to zero and becomes negative, indicating a reversal back towards home.
02

Plot Velocity Graph

Create a graph where the y-axis is the velocity and the x-axis is the time. 1. Start with a small positive velocity. 2. Graph a downward slope to zero to show the stop. 3. Increase the velocity quickly to a larger positive number. 4. Allow this constant large positive velocity for a period. 5. Graph a downward slope to zero. 6. Continue downward to a large negative number to show reversing direction.
03

Analyze Distance from Home

1. Initially, your distance from home will increase as velocity is positive. 2. Distance remains constant when velocity is zero (stopped condition). 3. As velocity becomes positive again, distance increases faster. 4. When velocity again reaches zero, distance remains constant. 5. Finally, as velocity is negative, the distance decreases indicating you are moving back toward home.
04

Plot Distance Graph

Create a graph where the y-axis is distance from home and the x-axis is time. 1. Start at zero distance. 2. Plot an upward slope indicating moving away as velocity is positive. 3. Draw a flat line when velocity is zero, showing no change in distance. 4. Plot a steeper upward slope when velocity increases, showing faster movement away. 5. Draw another flat line when velocity again becomes zero. 6. Finally, plot a downward slope when velocity is negative, indicating movement back towards home.
05

Create a Driving Story

Early one morning, you start your car trip from home. You drive slowly out of your neighborhood, slowing to a stop at a red light. When the light turns green, you speed up rapidly onto the freeway, maintaining high speed towards your destination. After a while, traffic slows and you eventually stop due to a traffic jam. Once the road clears, you turn around and drive quickly back home, reversing your trip and arriving back where you started.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Distance from Home
The concept of "Distance from Home" is pivotal when analyzing motion in physics, particularly through the lens of velocity changes. Imagine beginning a journey from your house. At the onset, you have a small positive velocity, suggesting you're gradually increasing the distance from your doorstep. As your car comes to a temporary halt, the distance remains unaltered since motion ceases momentarily.

When you pick up speed with a larger positive velocity, you cover more ground rapidly, causing the distance to expand quickly. However, should the velocity decrease back to zero, the distance halts but retains the previously accumulated value. The twist happens when the velocity turns negative, a clear indication of a return journey. This reversal implies the distance decreases as you inch closer to the origin point—your home. Understanding these shifts in distance is fundamentally important when examining motion using graphs.

  • Positive velocity means increasing distance
  • Zero velocity means distance remains constant
  • Negative velocity signals decreasing distance
Driving Story
To comprehend the narrative of your car trip, envision a story unfolding through the changes in velocity. You start gently pulling out of your driveway with a modest speed, symbolizing the beginning of your journey. Shortly thereafter, you encounter a stoplight. This momentary stop mimics a velocity drop to zero.

As the light turns green, you quickly accelerate, entering the expressway and maintaining a brisk pace. This phase represents a larger positive velocity, where you are progressing swiftly towards a destined point. Later, traffic conditions force you to slow down and eventually halt, portraying another zero velocity moment.

The final chapter involves turning around. Picture a detour that brings you back the way you came, now traveling with a negative velocity. The story ends when you pull into your driveway, completing the full round-trip— all mirrored in the velocity graph you create.
Graph Analysis
Creating and analyzing graphs of your journey can provide insightful visual understanding. Initially, on the velocity graph, you will begin with a slight rise, representing a small positive velocity as you start your trip. The downward slope to zero signifies your temporary stop at a light or sign.

Subsequently, an upward sharp rise reflects the increase in positive velocity as you merge onto the freeway, maintaining a constant speed. This plateau on the graph illustrates consistent movement away from your starting point. During the drive, traffic conditions may vary, culminating in another decrease to zero.

Later, a descending slope to a negative value depicts your change in direction, signifying a return home. For the distance graph, you'll observe a gradual upward slope becoming steeper as you accelerate, then flattening when at stop points before declining upon reversing direction.

  • Initial slope: Small positive velocity
  • Flat line at zero: No motion
  • Sharp rise: Quick acceleration
  • Downward slope: Reversing direction
Reversing Direction
Reversing direction is a crucial concept often explored through the lens of negative velocity. In our driving scenario, this moment signifies the transition from moving away from home to returning back.

Initially, velocity decrease reflects slowing down before stopping. Once the journey back begins, there's a distinct phase where the velocity graph showcases a dip below the zero mark, transitioning into a negative zone. This indicates a backward motion towards your starting point.

On the distance graph, this directional change manifests as a downward slope, signifying the decrease in the gap between your current location and home. A clear understanding of this phase not only helps with interpreting motion graphs but also with grasping how velocities and directions correlate in physical scenarios.

  • Velocity falls to zero before reversing
  • Negative velocity indicates moving back
  • Distance graph slope turns downward

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Water in a tank: Water is leaking out of a tank. The amount of water in the tank \(t\) minutes after it springs a leak is given by \(W(t)\) gallons. a. Explain what \(\frac{d W}{d t}\) means in practical terms. b. As water leaks out of the tank, is \(\frac{d W}{d t}\) positive or negative? c. For the first 10 minutes, water is leaking from the tank at a rate of 5 gallons per minute. What do you conclude about the nature of the function W during this period? d. After about 10 minutes, the hole in the tank suddenly gets larger, and water begins to leak out of the tank at 12 gallons per minute. i. Make a graph of W versus t. Be sure to incorporate linearity where it is appropriate. ii. Make a graph of dW dt versus t.

Sprinkler irrigation in Nebraska: Logistic growth can be used to model not only population growth but also economic and other types of growth. For example, the total number of acres \(A=A(t)\), in millions, in Nebraska that are being irrigated by modern sprinkler systems has shown approximate logistic growth since 1955 , closely following the equation of change $$ \frac{d A}{d t}=0.15 A\left(1-\frac{A}{3}\right) \text {. } $$ Here time \(t\) is measured in years. a. According to this model, how many total acres in Nebraska can be expected eventually to be irrigated by sprinkler systems? (Hint: This corresponds to the carrying capacity in the logistic model for population growth.) b. How many acres of land were under sprinkler irrigation when sprinkler irrigation was expanding at its most rapid rate?

A catfish farm: Catfish in a commercial pond can be expected to exhibit logistic population growth. Consider a pond with a carrying capacity of \(K=\) 4000 catfish. Take the \(r\) value for catfish in this pond to be \(r=0.06\). a. Write the equation of change for logistic growth of the catfish population. (Hint: If you have difficulty here, refer to Example 6.10.) b. Make a graph of \(\frac{d N}{d t}\) versus \(N\). c. For what values of \(N\) would the catfish population be expected to increase? d. For what values of \(N\) would the catfish population be expected to decrease? e. Recall from Section \(5.1\) that the maximum sustainable yield model says that a renewable resource should be maintained at a level where its growth rate is at a maximum, since this allows the population to replenish itself quickly. According to this model, at what level should the catfish population be maintained?

Chemical reactions: In a second-order reaction, one molecule of a substance \(A\) collides with one molecule of a substance \(B\) to produce a new substance, the product. If \(t\) denotes time and \(x=x(t)\) denotes the concentration of the product, then its rate of change \(\frac{d x}{d t}\) is called the rate of reaction. Suppose the initial concentration of \(A\) is \(a\) and the initial concentration of \(B\) is \(b\). Then, assuming a constant temperature, \(x\) satisfies the equation of change $$ \frac{d x}{d t}=k(a-x)(b-x) $$ for some constant \(k\). This is because the rate of reaction is proportional both to the amount of \(A\) that remains untransformed and to the amount of \(B\) that remains untransformed. Here we study a reaction between isobutyl bromide and sodium ethoxide in which \(k=0.0055, a=51\), and \(b=76\). The concentrations are in moles per cubic meter, and time is in seconds. 10 a. Write the equation of change for the reaction between isobutyl bromide and sodium ethoxide. b. Make a graph of \(\frac{d x}{d t}\) versus \(x\). Include a span of \(x=0\) to \(x=100\). c. Explain what can be expected to happen to the concentration of the product if the initial concentration of the product is 0 .

Falling with a parachute: When an average-size man with a parachute jumps from an airplane, he will fall \(S=12.5\left(0.2^{t}-1\right)+20 t\) feet in \(t \mathrm{sec}-\) onds. a. Plot the graph of \(S\) versus \(t\) over at least the first 10 seconds of the fall. b. How far does the parachutist fall in 2 seconds? c. Calculate \(\frac{d S}{d t}\) at 2 seconds into the fall and explain what the number you calculated means in practical terms.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.