A ranger in a national park is driving at 22.0 mi/h when a deer jumps into the road 180 ft ahead of the vehicle. After a reaction time t, the ranger applies the brakes to produce an acceleration of a = -8.00 ft/s2. What is the maximum reaction time allowed if she is to avoid hitting the deer? %3D

College Physics
11th Edition
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Raymond A. Serway, Chris Vuille
Chapter1: Units, Trigonometry. And Vectors
Section: Chapter Questions
Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...
icon
Related questions
icon
Concept explainers
Topic Video
Question
**Problem Statement:**

A ranger in a national park is driving at 22.0 mi/h when a deer jumps into the road 180 ft ahead of the vehicle. After a reaction time \( t \), the ranger applies the brakes to produce an acceleration of \( a = -8.00 \, \text{ft/s}^2 \). What is the maximum reaction time allowed if she is to avoid hitting the deer?

**Concepts Involved:**

- **Uniform Motion and Deceleration:** Understanding how initial velocity, acceleration, and distance relate in uniformly accelerated linear motion.
- **Kinematic Equations:** Using equations to determine time, distance, and velocity.

This problem involves converting the vehicle's speed from miles per hour to feet per second, calculating the stopping distance using kinematic equations, and then determining the reaction time.

---

1. **Speed Conversion:**
   - \( \text{Velocity in ft/s} = 22.0 \, \text{mi/h} \times \frac{5280 \, \text{ft/mi}}{3600 \, \text{s/h}} \) 

2. **Maximum Stopping Distance Equation:**
   - Use \( v^2 = u^2 + 2as \) where \( v = 0 \) (final velocity), \( u \) is initial velocity, \( a \) is acceleration, and \( s \) is stopping distance.

3. **Calculate Reaction Time:**
   - Find the total distance the vehicle travels during the driver's reaction time and braking to ensure it does not exceed 180 ft.

---

Teaching Notes:
- Analyzing reaction time and braking distance in real-life situations can help understand safety measures and the physics of motion.
- Encourage students to think about variables that may affect the outcome, such as road conditions and vehicle maintenance.
Transcribed Image Text:**Problem Statement:** A ranger in a national park is driving at 22.0 mi/h when a deer jumps into the road 180 ft ahead of the vehicle. After a reaction time \( t \), the ranger applies the brakes to produce an acceleration of \( a = -8.00 \, \text{ft/s}^2 \). What is the maximum reaction time allowed if she is to avoid hitting the deer? **Concepts Involved:** - **Uniform Motion and Deceleration:** Understanding how initial velocity, acceleration, and distance relate in uniformly accelerated linear motion. - **Kinematic Equations:** Using equations to determine time, distance, and velocity. This problem involves converting the vehicle's speed from miles per hour to feet per second, calculating the stopping distance using kinematic equations, and then determining the reaction time. --- 1. **Speed Conversion:** - \( \text{Velocity in ft/s} = 22.0 \, \text{mi/h} \times \frac{5280 \, \text{ft/mi}}{3600 \, \text{s/h}} \) 2. **Maximum Stopping Distance Equation:** - Use \( v^2 = u^2 + 2as \) where \( v = 0 \) (final velocity), \( u \) is initial velocity, \( a \) is acceleration, and \( s \) is stopping distance. 3. **Calculate Reaction Time:** - Find the total distance the vehicle travels during the driver's reaction time and braking to ensure it does not exceed 180 ft. --- Teaching Notes: - Analyzing reaction time and braking distance in real-life situations can help understand safety measures and the physics of motion. - Encourage students to think about variables that may affect the outcome, such as road conditions and vehicle maintenance.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Displacement, velocity and acceleration
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
College Physics
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
Physics for Scientists and Engineers
Physics for Scientists and Engineers
Physics
ISBN:
9781337553278
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:
9780321820464
Author:
Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:
Addison-Wesley
College Physics: A Strategic Approach (4th Editio…
College Physics: A Strategic Approach (4th Editio…
Physics
ISBN:
9780134609034
Author:
Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:
PEARSON