Which of the following activities will allow an engineer to determine that a building's design is sound?

A long aluminum wire of diameter 3 mm is extruded at a temperature of 280°C. The wire is subjected to cross air flow at 20°C at

Musya8 [376]

Answer:

Explanation:

Given:

Diameter of aluminum wire, D = 3mm

Temperature of aluminum wire, $T_{s}=280^{o}C$

Temperature of air, $T_{\infinity}=20^{o}C$

Velocity of air flow $V=5.5m/s$

The film temperature is determined as:

$T_{f}=\frac{T_{s}-T_{\infinity}}{2}\\\\=\frac{280-20}{2}\\\\=150^{o}C$

from the table, properties of air at 1 atm pressure

At $T_{f}=150^{o}C$

Thermal conductivity, $K = 0.03443 W/m^oC$ ; kinematic viscosity $v=2.860 \times 10^{-5} m^2/s$ ; Prandtl number $Pr=0.70275$

The reynolds number for the flow is determined as:

$Re=\frac{VD}{v}\\\\=\frac{5.5 \times(3\times10^{-3})}{2.86\times10^{-5}}\\\\=576.92$

sice the obtained reynolds number is less than $2\times10^5$ , the flow is said to be laminar.

The nusselt number is determined from the relation given by:

$Nu_{cyl}= 0.3 + \frac{0.62Re^{0.5}Pr^{\frac{1}{3}}}{[1+(\frac{0.4}{Pr})^{\frac{2}{3}}]^{\frac{1}{4}}}[1+(\frac{Re}{282000})^{\frac{5}{8}}]^{\frac{4}{5}}$

$Nu_{cyl}= 0.3 + \frac{0.62(576.92)^{0.5}(0.70275)^{\frac{1}{3}}}{[1+(\frac{0.4}{(0.70275)})^{\frac{2}{3}}]^{\frac{1}{4}}}[1+(\frac{576.92}{282000})^{\frac{5}{8}}]^{\frac{4}{5}}\\\\=12.11$

The covective heat transfer coefficient is given by:

$Nu_{cyl}=\frac{hD}{k}$

Rewrite and solve for $h$

$h=\frac{Nu_{cyl}\timesk}{D}\\\\=\frac{12.11\times0.03443}{3\times10^{-3}}\\\\=138.98 W/m^{2}.K$

The rate of heat transfer from the wire to the air per meter length is determined from the equation is given by:

$Q=hA_{s}(T_{s}-T{\infin})\\\\=h\times(\pi\timesDL)\times(T_{s}-T{\infinity})\\\\=138.92\times(\pi\times3\times10^{-3}\times1)\times(280-20)\\\\=340.42W/m$

The rate of heat transfer from the wire to the air per meter length is $Q=340.42W/m$

6 0

3 years ago

What are three demonstration drive tips for the vc-turbo engine?.

Oliga [24]

The three (3) demonstration drive tips for a VC-turbo engine are:

Use your gears when overtaking and driving up a long hill.
Warm up your engine before accelerating.
Ensure your oil level is at the optimum gauge or level.

<h3>What is a VC-turbo engine?</h3>

A VC-turbo engine can be defined as a technologically-advanced internal combustion engine that is design and developed to be faster, especially by combining the torque and efficiency of an advanced diesel powertrain with the power of a high-performance gas engine.

<h3>The demonstration drive tips.</h3>

Basically, the three (3) demonstration drive tips for a VC-turbo engine include the following:

Use your gears when overtaking and driving up a long hill.
Warm up your engine before accelerating.
Ensure your oil level is at the optimum gauge or level.

Read more on drive tips here: brainly.com/question/23968178

4 0

3 years ago

Chegg Discuss why stress-strain behavior of material is critical than just the ultimate strength of the material. What propertie

DanielleElmas [232]

Answer:

Throughout the clarification section elsewhere here, the definition of the concern is mentioned.

Explanation:

The stress-strain curve provides designers with a long list of critical parameters that are needed for utility development. Including capacity, longevity, elasticity, apparent viscosity, tension electricity, resilience, as well as flexural strength, a load-pressure assignment gave us several mechanical households at a certain point of operation. It also assists in manufacturing.
During which the overarching force can inform us about the maximum energy either workload the substance will experience, which could also be inferred within the action of the stress-strain. The dynamic properties can be seen by pre maximum activity because it will be before even the maximum yield intensity as well as the posted maximum would display plastic behavior however after the peak becomes achieved, the natural frequencies continue to decline.

4 0

3 years ago

What is the subtotal for the building materials in the bill? The subtotal should be the cost of the materials only. Don't add ta

Alexxx [7]

Answer:

Cost before adding taxes and incorporating variations

Explanation:

The sub-totals are basically sum of the cost from individual pages before including value added tax or any other tax depending with the state regulations. At this stage, contingencies and variation of prices are not considered. Therefore, the sub-total for building materials only include the materials on site or materials used as per the bill of quantities and certified by the engineer.

3 0

4 years ago

A square steel bar has a length of 8.4 ft and a 2.1 in by 2.1 in cross section and is subjected to axial tension. The final leng

nikitadnepr [17]

Answer:

Poissons ratio = -0.3367

Explanation:

Poissons ratio = Lateral Strain / Longitudinal Strain

In this case, the longitudinal strain will be:

Strain (longitudinal) = Change in length / total length

Strain (longitudinal) = (8.40392 - 8.4) / 8.4

Strain (longitudinal) = 4.666 * 10^(-4)

While the lateral strain will be:

Strain (Lateral) = Change in length / total length

Strain (Lateral) = (2.09967 - 2.1) / 2.1

Strain (Lateral) = -1.571 * 10^(-4)

Solving the poisson equation at the top we get:

Poissons ratio = -1.571 / 4.666 <u>( 10^(-4) cancels out )</u>

Poissons ratio = -0.3367

6 0

3 years ago