All categories

3 years ago

Select the correct answer.

Engineering

1 answer:

melomori [17]3 years ago

3 0

Answer:

starburst

Explanation:

There are many different kinds of "hazard symbols," which are being used in order for people to recognize what kind of material they are handling. When it comes to "pictograms," the symbol for a hazard class of explosive is an exploding bomb that shows a starburst effect. An example of such chemical is the "organic peroxide" and other self-reactive chemicals.

A "flame" is a hazard symbol for flammable substances. A "gas cylinder" is a hazard symbol for gases that are located in containers that are under pressure. A "test tube" is a hazard symbol for substances/materials that cause corrosion to skin.

You might be interested in

Air is compressed slowly in a piston-cylinder assembly from an initial state where P1 = 1.4 bar, V1= 4.25 m^3, to a final state

lord [1]

Answer:

W=-940.36 KJ

Explanation:

Given that

$P_1=1\ bar,V_1=4.25 {m^3}$

$P_2=6.8\ bar$

Process follows pv=constant

So this is the isothermal process and work in isothermal process given as

$W=P_1V_1\ln \dfrac{P_1}{P_2}$

Now by putting the values (1.4 bar =140 KPa)

$W=P_1V_1\ln \dfrac{P_1}{P_2}$

$W=140\times 4.25 \ln \dfrac{1.4}{6.8}$

W=-940.36 KJ

Negative sign indicates that this is a compression process and work will given to the system.

7 0

4 years ago

Which of the following types of protective equipment protects workers who are passing by from stray sparks or metal while anothe

lawyer [7]

A protective equipment which protects workers who are passing by from stray sparks or metal while another worker is welding is: E. Welding Screens.

A wielder refers to an individual who is saddled with responsibility of joining two or more metals together by wielding.

During the process of wielding, sparks and minute metallic objects are produced, which are usually hazardous to both the wielder and other workers within the vicinity.

Hence, the following protective equipment are meant to be worn or used directly by a wielder (worker) who is wielding:

Visors.

Goggles.

Protective clothing.

Dark walls.

However, a protective equipment which protects other workers who are passing by from stray sparks or metallic objects while wielder (worker) is welding is referred to as welding screens.

Find more information: brainly.com/question/15442363

4 0

3 years ago

2.11 Consider a 400 mm × 400 mm window in an aircraft. For a temperature difference of 90°C from the inner to the outer surface

alexandr402 [8]

Answer:

The heat loss rate through one of the windows made of polycarbonate is 252W. If the window is made of aerogel, the heat loss rate is 16.8W. If the window is made of soda-lime glass, the heat loss rate is 1190.4W.

The cost associated with the heat loss through the windows for an 8-hour flight is:

For aerogel windows: $17.472 (most efficient)

For polycarbonate windows: $262.08

For soda-lime glass windows: $1,238.016 (least efficient)

Explanation:

To calculate the heat loss rate through the window, we can use a model of heat transmission by conduction throw flat wall. Using unidimensional Fourier law:

$\frac{dQ}{dt}=\dot Q =-kS\nabla \vec{T}$

In this case:

$\dot Q =k\frac{S}{L} \Delta T$

If we replace the data provided by the problem we get the heat loss rate through one of the windows of each material (we only have to change the thermal conductivities).

To obtain the thermal conductivity of the soda-lime glass we use the graphic attached to this answer (In this case for soda-lime glass k₃₀₀=0.992w/m·K).

To calculate the cost associated with the heat loss through the windows for an 8-hour flight we use this formula (using the heat loss rate calculated in each case):

$Cost=C_{hc}\cdot \dot Q \cdot t \cdot n=1\frac{\$}{Kwh} \cdot \dot Q \cdot 8h \cdot 130$

6 0

3 years ago

Compute the repeat unit molecular weight of PTFE. Also compute the number-average molecular weight for a PTFE for which the degr

MatroZZZ [7]

Answer:

a) the repeat unit molecular weight of PTFE MW = 100.015 g/mole

b) the number-average molecular weight for a PTFE for which the degree of polymerization is 10,000 щₙ = 1000150 g/mole

Explanation:

Given that;

PTFE which is also called Polytetrafluoroethylene

structure of repeat unit of Polytetrafluoroethylene

(C2F4)n

To compute the repeat unit molecular weight

we say

MW = 2( atomic weight of C ) + 4( atomic weight of F)

MW = 2 (12.0107) + 4 ( 18.9984)

MW = 100.015 g/mole

therefore the repeat unit molecular weight of PTFE MW = 100.015 g/mole

To compute the number-average molecular weight for PTFE of which the degree of polymerization is 10,000

we say

DP = щₙ / MW

where щₙ is the number of average molecular weight,

MW is the repeat unit molecular weight give as 100.015 g/mole

DP is degree of polymerization which is 10,000

Now we substitute

10,000 = щₙ / 100.015

щₙ = 10,000 × 100.015

щₙ = 1000150 g/mole

Therefore the number-average molecular weight for a PTFE for which the degree of polymerization is 10,000 щₙ = 1000150 g/mole

3 0

3 years ago

If a structure can withstand seismic stress, what is it prepared for?.

mars1129 [50]

Answer:

Steel and wood

Explanation:

For a material to resist stress and vibration, it must have high ductility, which is the ability to undergo large deformations and tension. Modern buildings are often constructed with structural steel, a component that comes in a variety of shapes and allows buildings to bend without breaking.

4 0

2 years ago