Homework Help is Here – Start Your Trial Now!
Engineering
Civil Engineering
Problem 1. In deriving braking distance, we assume a constant acceleration/deceleration rate, a. In fact, AASHTO assumes constant acceleration a(t) = c (constant) in most of its design procedures. Although this is not entirely true, distances required for acceleration or deceleration can be realistic if appropriate values are chosen for the constant acceleration process. Linear acceleration a(t) = C₁ ⋅t (t is time elapse and c₁ is jerk rate or rate of change) is a better approximation to the acceleration process. a) What is the practical stopping distance for a vehicle with initial speed 70 mph, if acceleration is described by a linear function of time using a(t) = -1.8t (t is time elapse in seconds). Use a constant acceleration rate to achieve the same stopping distance. What is this constant acceleration rate? b)

Problem 1. In deriving braking distance, we assume a constant acceleration/deceleration rate, a. In fact, AASHTO assumes constant acceleration a(t) = c (constant) in most of its design procedures. Although this is not entirely true, distances required for acceleration or deceleration can be realistic if appropriate values are chosen for the constant acceleration process. Linear acceleration a(t) = C₁ ⋅t (t is time elapse and c₁ is jerk rate or rate of change) is a better approximation to the acceleration process. a) What is the practical stopping distance for a vehicle with initial speed 70 mph, if acceleration is described by a linear function of time using a(t) = -1.8t (t is time elapse in seconds). Use a constant acceleration rate to achieve the same stopping distance. What is this constant acceleration rate? b)

Structural Analysis
Structural Analysis
6th Edition
ISBN:9781337630931
Author:KASSIMALI, Aslam.
Publisher:KASSIMALI, Aslam.
Chapter2: Loads On Structures
Section: Chapter Questions
Problem 1P
See similar textbooks
icon
Related questions
Question
Problem 1. In deriving braking distance, we assume a constant acceleration/deceleration rate, a. In fact, AASHTO assumes constant acceleration a(t): = c (constant) in most of its design procedures. Although this is not entirely true, distances required for acceleration or deceleration can be realistic if appropriate values are chosen for the constant acceleration process. Linear acceleration a(t) = c₁t (t is time elapse and c₁ is jerk rate or rate of change) is a better approximation to the acceleration process. a) What is the practical stopping distance for a vehicle with initial speed 70 mph, if acceleration is described by a linear function of time using a(t) = -1.8t (t is time elapse in seconds). b) Use a constant acceleration rate to achieve the same stopping distance. What is this constant acceleration rate? Problem 2. A car hits a tree at an estimated speed of 25 mph on a 3 % upgrade. If skid marks of 120 ft are observed on dry pavement (coefficient of braking friction, fo =0.35) followed by 250 ft (f =0.25) on a grass stabilized shoulder, estimate the initial speed of the vehicle just before the pavement skid began. Problem 3. Drivers must slow down from 60 mph to 40 mph to negotiate a severe curve on a rural highway. A warning sign is determined to be visible from 120 ft. away. How far must the sign be located, in advance of the curve, to ensure that vehicles have sufficient distance to decelerate? Use the standard reaction time and deceleration rate recommended by AASHTO for basic braking maneuvers.
Transcribed Image Text:Problem 1. In deriving braking distance, we assume a constant acceleration/deceleration rate, a. In fact, AASHTO assumes constant acceleration a(t): = c (constant) in most of its design procedures. Although this is not entirely true, distances required for acceleration or deceleration can be realistic if appropriate values are chosen for the constant acceleration process. Linear acceleration a(t) = c₁t (t is time elapse and c₁ is jerk rate or rate of change) is a better approximation to the acceleration process. a) What is the practical stopping distance for a vehicle with initial speed 70 mph, if acceleration is described by a linear function of time using a(t) = -1.8t (t is time elapse in seconds). b) Use a constant acceleration rate to achieve the same stopping distance. What is this constant acceleration rate? Problem 2. A car hits a tree at an estimated speed of 25 mph on a 3 % upgrade. If skid marks of 120 ft are observed on dry pavement (coefficient of braking friction, fo =0.35) followed by 250 ft (f =0.25) on a grass stabilized shoulder, estimate the initial speed of the vehicle just before the pavement skid began. Problem 3. Drivers must slow down from 60 mph to 40 mph to negotiate a severe curve on a rural highway. A warning sign is determined to be visible from 120 ft. away. How far must the sign be located, in advance of the curve, to ensure that vehicles have sufficient distance to decelerate? Use the standard reaction time and deceleration rate recommended by AASHTO for basic braking maneuvers.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps with 3 images

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Knowledge Booster
Work and energy
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Structural Analysis
Structural Analysis
Civil Engineering
ISBN:
9781337630931
Author:
KASSIMALI, Aslam.
Publisher:
Cengage,
Structural Analysis (10th Edition)
Structural Analysis (10th Edition)
Civil Engineering
ISBN:
9780134610672
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Principles of Foundation Engineering (MindTap Cou…
Principles of Foundation Engineering (MindTap Cou…
Civil Engineering
ISBN:
9781337705028
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning
Fundamentals of Structural Analysis
Fundamentals of Structural Analysis
Civil Engineering
ISBN:
9780073398006
Author:
Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:
McGraw-Hill Education
Sustainable Energy
Sustainable Energy
Civil Engineering
ISBN:
9781337551663
Author:
DUNLAP, Richard A.
Publisher:
Cengage,
Traffic and Highway Engineering
Traffic and Highway Engineering
Civil Engineering
ISBN:
9781305156241
Author:
Garber, Nicholas J.
Publisher:
Cengage Learning
SEE MORE TEXTBOOKS