1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
oksano4ka [1.4K]
3 years ago
14

An engineering student claims that a country road can be safely negotiated at 65 mi/h in rainy weather. Because of the winding n

ature of the road, one stretch of level pavement has a sight distance of only 510 ft. Assuming practical stopping distance, comment on the student
Engineering
1 answer:
igomit [66]3 years ago
4 0

Answer:

Negotiated speed should be lower. Perception/reaction time is too less than design values.

Explanation:

Given:

- The claimed safe speed V_1 = 65 mi/h

- Sight distance D = 510 ft

- The practical deceleration a = 11.2 ft/s   ... according to standards

Find:

Assuming practical stopping distance, comment on the student whether the claim is correct or not

Solution:

- Calculate the practical stopping distance:

                      d = V_1^2 / 2*a

                      d = ( 65 * 1.46 )^2 / 2*11.2 = 402.054 ft

- Solve for reaction distance d_r is as follows:

                     d_r = D - d = 510 - 402.054 = 107.945 ft

- The perception/time reaction is:

                   t_r = d_r/V_1 = 107.945 / 94.9

                  t_r = 1.17 sec

Answer: The perception/reaction time t_r = 1.17 s is well below the t = 2.3 s.

Hence, the safe speed should be lower.

You might be interested in
Which of the following BEST represents the causes of stiff muscles?
Ulleksa [173]
A stiff muscles onky result from overwork
5 0
3 years ago
Select the correct answer.
uysha [10]

Answer:

Lazermicrometer 100%

Explanation:

3 0
4 years ago
A continuous fiber-reinforced composite is to be produced by dispersing 60 vol% carbon fibers in a polycarbonate matrix. if the
devlian [24]

Answer:

Explanation:

A continuous fiber-reinforced composite is to be produced by dispersing 60 vol% carbon fibers in a polycarbonate matrix. if the stress in the polycarbonate matrix when the carbon fibers fail is 45 mpa, the longitudinal elastic modulus of the composite using rule of mixture

5 0
2 years ago
Write a naive implementation (i.e. non-vectorized) of matrix multiplication, and then write an efficient implementation that uti
erik [133]

Answer:

import numpy as np  

import time  

def matrixMul(m1,m2):      

   if m1.shape[1] == m2.shape[0]:  

       

       t1 = time.time()

       r1 = np.zeros((m1.shape[0],m2.shape[1]))

       for i in range(m1.shape[0]):

           for j in range(m2.shape[1]):

               r1[i,j] = (m1[i]*m2.transpose()[j]).sum()

       t2 = time.time()

       print("Native implementation: ",r1)

       print("Time: ",t2-t1)

       

       t1 = time.time()

       r2 = m1.dot(m2)

       t2 = time.time()

       print("\nEfficient implementation: ",r2)

       print("Time: ",t2-t1)

       

   else:

       print("Wrong dimensions!")

Explanation:

We define a function (matrixMul) that receive two arrays representing the two matrices to be multiplied, then we verify is the dimensions are appropriated for matrix multiplication if so we proceed with the native implementation consisting of two for-loops and prints the result of the operation and the execution time, then we proceed with the efficient implementation using .dot method then we return the result with the operation time. As you can see from the image the execution time is appreciable just for large matrices, in such a case the execution time of the efficient implementation can be 1000 times faster than the native implementation.

7 0
3 years ago
The correct statement about the lift and drag on an object is:_______
Lisa [10]

Answer:

(a). the resultant force in the direction of the freestream velocity is termed the drag and the resultant force normal to the freestream velocity is termed the lift

Explanation:

When a fluid flows around the surface of an object, it exerts a force on it. This force has two components, namely lift and drag.

The component of this force that is perpendicular (normal) to the freestream velocity is known as lift, while the component of this force that is parallel or in the direction of the fluid freestream flow is known as drag.

Lift is as a result of pressure differences, while drag results from forces due to pressure distributions over the object surface, and forces due to skin friction or viscous force.

Thus, drag results from the combination of pressure and viscous forces while lift results only from the<em> pressure differences</em> (not pressure forces as was used in option D).

The only correct option left is "A"

(a). the resultant force in the direction of the freestream velocity is termed the drag and the resultant force normal to the freestream velocity is termed the lift

8 0
4 years ago
Read 2 more answers
Other questions:
  • There are four distinct events that occur in the Carnot cycle. Name the events and describe each one.
    15·1 answer
  • A composite wall is composed of 20 cm of concrete block with k = 0.5 W/m-K and 5 cm of foam insulation with k = 0.03 W/m-K. The
    13·1 answer
  • Consider a rectangular wing mounted in a full-scale wind tunnel. The wing model completely spans the test section so that the fl
    6·1 answer
  • What Is the Job Demand for Solar Engineers?<br> (2 or more sentences please and thank you)
    9·1 answer
  • What is your favorite RPG game? ( Role Play Game)
    5·2 answers
  • What is a chipping hammer used for? <br><br> State three things.
    7·2 answers
  • How to report the analysis and calorific values of fuel​
    6·1 answer
  • What is the horsepower of a 302 engine
    10·2 answers
  • The primary of an ideal transformer has 400 turns and its secondary has 200 turns. Neglecting electrical losses, if the power in
    7·1 answer
  • Determine the normal stress acting perpendicular to the seam, when the tube is subjected to an axial compressive force of 200
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!