Concept explainers
Calculate the total distance traveled by the car and the average speed of the car. Plot the acceleration of car as a function of time.
Answer to Problem 28P
The total distance traveled by car is
Explanation of Solution
Refer to the figure Problem 8.28 in the textbook for the speed versus time characteristics of the car.
During the initial 20 seconds, the speed of the car increases linearly from a value of zero to 60 mph. Therefore, the average speed of the car is 30 mph during this period. The distance traveled during this period is,
During the next 20 minutes the car moves with a constant speed of 60 mph and the distance traveled during this period is,
Because the car decelerates at a constant rate from a speed of 60 mph to 0 mph, the average speed of the car during the last 10 seconds is also 30 mph, and the distance traveled during this period is,
The total distance traveled is
Substitute 880 feet for
Give the expression for average speed of the car for the entire duration of travel as below.
Substitute
To plot the acceleration of car as a function of time, calculate the acceleration during the first 20 seconds, the next 20 minutes, and the last 10 seconds.
Calculate the acceleration of the car during the initial 20 seconds as below.
Note during this 20 seconds period, the speed of car changes from 0 to
During the next 20 minutes, the car moves with constant speed of 60 mph. Therefore, the acceleration is zero.
Show the plot of acceleration versus time as in Figure 1.
Conclusion:
Thus, the total distance traveled by car is
Want to see more full solutions like this?
Chapter 8 Solutions
ENGINEERING FUNDAMENTALS
- The acceleration record shown was obtained during the speed trials of a sports car. Knowing that the car starts from rest, determine by approximate means (a) the velocity of the car at t= 8 s, (b) the distance the car has traveled at t= 20 s.arrow_forwardDetermine the acceleration of the particle moving in a circular path as shown below at the instant that its velocity is 1m/s while its tangential acceleration is 2m/s².arrow_forwardThe figure shows a train traveling at a constant uniform velocity of 75 kph and a car travelling at a speed of 36 kph towards point 0. A. Which of the following gives the nearest value of the acceleration of the car, if the car reaches point 0, 10 seconds ahead than that of the train. B. If the train moves at a uniform velocity, which of the following gives nearest value of the required time for the train to reach the point 0. C. Using the acceleration computed, which of the following gives the value of the velocity of the car at the collision point.arrow_forward
- A car is initially at rest on a straight road. The graph shows the speed of the car as a function of time. (s/w) A 12 11 10 9 8 7 5 4 3 2 1 B 1 0 2 A 7 t(s) What is the speed of the car at t=7 s? 3 4 5 6 8 9 Submit Answer Tries 0/12 10 11 12 13 Submit Answer Tries 0/12 How much distance did the car cover in the first 8 seconds? Determine the distance covered by the car between t=9 s and t=14 s? Submit Answer Tries 0/12 What is the average speed of the car between t=4 s and t=7 s? 14arrow_forward4. A car is traveling at a constant speed of 130 kph at a location where the speed limit is 100 kph. A police officer gives chase and from rest begins to accelerate at the constant rate of 6 m/s2 until a speed of 160 kph is reached and maintained. How much distance is required for the officer to over- take car A. Set your own variables for each parameter as you see fit. 5. A projectile is fired downward in an experimental fluid and experiences an acceleration of a = o-nv², where o and n are positive constants and v representing the velocity. Determine the distance travelled by the projectile when its velocity has been reduced to half. Determine also the terminal velocity. Evaluate for a = 0.7 m/s², n = 0.2 m-¹, and initial velocity of 4 m/s.arrow_forward1. An engineer is traveling in a straight road using his newly acquired Toyota Fortuner and found himself 120 m away from his starting point after 10 seconds. After traveling for two more seconds, he was found to be 132 m from his starting point. If he is moving with constant acceleration, determine: (a) his initial velocity (m/s), (b) his constant acceleration (m/s²),arrow_forward
- As shown in the figure below, a motorist starts from rest at point A on a circular entrance ramp when t = 0, increases the speed of her automobile at a constant rate and enters the highway at point B. Knowing that her speed continues to increase at the same rate until it reaches 80 km/h at point C, determine (a) the speed at point B, (b) the magnitude of the total acceleration when t = 12 s. -100 m → 150 m •Aarrow_forwardPROBLEM 1: A car starting from rest is moving at constant acceleration until it reached final velocity of 19 m/s after traveling a distance of 153.2 m. Calculate the acceleration and the time required.arrow_forwardAt the instant shown, cars A and B are traveling at the speeds shown. If B is accelerating at 1036 km/h2 while A maintains a constant speed, determine the acceleration of A with respect to B in km/hr². VA = 18.5 m/s; VB = 55 m/s; p = 103 m 100 m Va B V8arrow_forward
- A Circular Roadway and the Acceleration of Your Car "T (decreasing) (a) Constant angular speed (b) Decreasing angular speed Suppose you are driving a car in a counterclockwise direction on a circular road whose radius is r= 390 m (see Figure 8.20). You look at the speedometer and it reads a steady 32 m/s (about 72 mi/h). (a) What is the angular speed of the car? (b) Determine the acceleration (magnitude and direction) of the car. (c) To avoid a rear-end collision with a vehicle ahead, you apply the brakes and reduce your angular speed to 4.9 x 10-2 rad/s in a time of 4.0 s. What is the tangential acceleration (magnitude and direction) of the car?arrow_forwardA car traveling at 30 m/sec has wheels with 75cm diameters. Find: angular speed of wheels, if the car stops in 5 sec, what is angular acceleration? how many revolutions do the wheels turn before stopping?arrow_forwardIn traveling a distance of 2.3 km between points A and D, a car is driven at 91 km/h from A to B for t seconds and 43 km/h from C to D also for t seconds. If the brakes are applied for 3.7 seconds between B and C to give the car a uniform deceleration, calculate t and the distances between A and B. Answers: t= S= 91 km/h i B 2.3 km 43 km/h S km Darrow_forward
- Engineering Fundamentals: An Introduction to Engi...Civil EngineeringISBN:9781305084766Author:Saeed MoaveniPublisher:Cengage Learning