1. A _____ is applied to a wall or roof rafters to add strength and keep the building straight and plumb.

The water in a 25-m-deep reservoir is kept inside by a 140-m-wide wall whose cross section is an equilateral triangle as shown i

koban [17]

Answer: (a) 9.00 Mega Newtons or 9.00 * 10^6 N

(b) 17.1 m

Explanation: The length of wall under the surface can be given by

$b=25m/sin(60)\\=28.867$

The average pressure on the surface of the wall is the pressure at the centeroid of the equilateral triangular block which can be then be calculated by multiplying it with the Plate Area which will provide us with the Resultant force.

$F(resultant) = Pavg ( A) = (Patm + \rho g h c)*A \\= [100000 N/m^2 + (1000 kg/m^3 * 9.81 m/s^2 * 25m/2)]* (140*25m/sin60)\\= 8.997*10^8 N \\= 9.0*10^8 N$

Noting from the Bernoulli equation that

$Po/\rho g sin60 = 100000/1000 * 9.81* sin(60) = 11.77 m \\ \\$

From the second image attached the distance of the pressure center from the free surface of the water along the surface of the wall is given by:

$Yp = s+\frac{b}{2} +\frac{b^2}{s+\frac{b}{2}+Po/\rho g sin60}= 0+\frac{28.87}{2} +\frac{28.87^2}{0+\frac{28.87}{2}+100000 /1000 *9.81 sin60} = 17.1 m$

Substituting the values gives us the the distance of the surface to be equal to = 17.1 m

7 0

2 years ago

Write a python program to apply this:

lakkis [162]

Answer:

# Initialize a dictionary with the keys

contestants = {"Darci Lynne":0, "Angelica Hale":0, "Angelina Green":0};

# Repeatedly prompt the user for a contestant name to vote for

while True:

# Prompting user for contestant name

cName = input("Enter contestant name to vote: ");

# Checking for Done

if cName.lower() == "done":

break;

# Checking in dictionary

if cName in contestants.keys():

# Updating vote value

contestants[cName] += 1

# New entry

else:

contestants[cName] = 1

# Printing header

print("\n%-20s %-15s\n" %("Contestant Name", "Votes Casted"))

# Printing results

for contestant in contestants:

print("%-23s %-15d" %(contestant, contestants[contestant]))

8 0

3 years ago

1. If you look at a reaction equation for a Fischer esterification reaction, you cannot tell where the oxygen comes from (acid o

Yanka [14]

Answer:

Explained

Explanation:

In the experiment, an (18)O-labelled alcohol R('18)OH is used with normal unlabeled carboxylic acid RC(16)O2H:

The esterification reaction is:

(note: the bracketed values are atomic masses)

RC(16)O_2H + R'(18)OH => RC16O18OR' + H_2(16)O

Since the alcohol is the nucleophile in this nucleophilic substitution reaction, it adds to the carbonyl group of the carboxylic acid and the (18)O atom becomes incorporated into the ester product, while the (16)OH group of the carboxylic acid is expelled as H_2(16)O.

By using mass spectroscopy to measure the mass of the ester and water products, it can be shown that each ester molecule contains one (18)O atom and one (16)O atom, while the water molecules contains only (16)O atoms.

This would prove unequivocally that the ester contains one O atom from the carboxylic acid and one O atom from the alcohol, while the water contains only O atoms from the carboxylic acid.

7 0

3 years ago

What are two ways you can see that there is a smaller load going to the base of the transistor?

Lyrx [107]

Answer:

<h3>Transistor switches can be used to switch a low voltage DC device (e.g. LED’s) ON or OFF by using a transistor in its saturated or cut-off state</h3>

. Cut-off Region

Here the operating conditions of the transistor are zero input base current ( IB ), zero output collector current ( IC ) and maximum collector voltage ( VCE ) which results in a large depletion layer and no current flowing through the device. Therefore the transistor is switched “Fully-OFF”.

2.Saturation Region

Here the transistor will be biased so that the maximum amount of base current is applied, resulting in maximum collector current resulting in the minimum collector emitter voltage drop which results in the depletion layer being as small as possible and maximum current flowing through the transistor. Therefore the transistor is switched “Fully-ON”.

Explanation:

hope it helps

7 0

2 years ago

A 60-m-long steel wire is subjected to a 6-kN tensile load. Knowing that E = 200 GPa and that the length of the rod increases by

Talja [164]

Answer:

(a) 6.91 mm (b) 160 MPa

Explanation:

Solution

Given that:

E = 200 GPa

The rod length = 48 mm

P =P¹ = 6 kN

Recall that,

1 kN = 10^3 N

1 m =10^3 mm

I GPa = 10^9 N/m²

Thus

The rod deformation is stated as follows:

δ = PL/AE-------(1)

σ = P/A----------(2)

Now,

(a) We substitute the values in equation and obtain the following:

48 * 10 ^⁻3 m = (6 * 10³ N) (60 m)/A[ 200 * 10^9 N/m^2]

Thus, we simplify

A = (6 * 10³) (60)/ ( 200 * 10^9) (48 * 10 ^⁻3)m²

A =0.0375 * 10 ^⁻3 m²

A =37.5 mm²

A = π/4 d²

Thus,

d² = 4A /π

After inserting the values we have,

d = √37.5 * 4/3.14 mm

= 6.9116 mm

or d = 6.91 mm

Therefore, the smallest that should be used is 6.91 mm

(B) To determine the corresponding normal stress that is caused by the tensile force, we input the values in equation (2)

Thus,

σ = P/A

σ= 6 * 10 ^ 3 N/ 37. 5 * 10 ^⁻6 m²

σ= 160 MPa

Note: I MPa = 10^6 N/m²

Hence the the corresponding normal stress is σ= 160 MPa

5 0

2 years ago