Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 2h 22m
4. Applications of Derivatives
Motion Analysis
Problem 3.6.40b
Textbook Question
Velocity of a car The graph shows the position s=f(t) of a car t hours after 5:00 P.M. relative to its starting point s=0,where s is measured in miles. <IMAGE>
b. At approximately what time is the car traveling the fastest? The slowest?

1
To determine when the car is traveling the fastest or the slowest, we need to analyze the graph of the position function s=f(t). The speed of the car is given by the derivative of the position function, which is the velocity v(t)=f'(t).
Identify the points on the graph where the slope of the tangent line is the steepest. The steepest positive slope indicates the fastest speed, while the steepest negative slope indicates the slowest speed.
Look for the points on the graph where the slope changes from positive to negative or vice versa. These points are typically where the velocity is zero, indicating a change in direction or a stop.
Estimate the time t at which these slopes occur by observing the graph. The time when the slope is steepest positive corresponds to the fastest speed, and the time when the slope is steepest negative corresponds to the slowest speed.
Consider the context of the problem: the graph represents the position relative to the starting point at 5:00 P.M. Use this information to convert the time t into actual clock time for your final answer.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Velocity and Speed
Velocity is the rate of change of position with respect to time, represented mathematically as the derivative of the position function, s=f(t). Speed, a scalar quantity, refers to how fast an object is moving regardless of direction. Understanding how to interpret the graph of position versus time is crucial for determining when the car is traveling fastest or slowest.
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Critical Points
Critical points occur where the derivative of a function is zero or undefined, indicating potential local maxima or minima. In the context of the car's velocity, these points on the graph of the position function can help identify when the car is at its fastest or slowest speeds. Analyzing these points allows us to determine changes in the car's motion.
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Graph Interpretation
Interpreting graphs involves analyzing the shape and features of the graph to extract meaningful information. For the position-time graph of the car, the slope at any point indicates the car's velocity. A steeper slope corresponds to higher speeds, while a flatter slope indicates slower speeds, which is essential for answering the question about the car's speed at different times.
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