Questions
Newton's second law of motion can always be used to derive the equations of motion of...

Newton's second law of motion can always be used to derive the equations of motion of a vibrating system

In: Mechanical Engineering

At 180°C the heat of vaporization, AvapH of a certain liquid is 14.4 kJ mol'1 ....

At 180°C the heat of vaporization, AvapH of a certain liquid is 14.4 kJ mol'1 . The molar volumes of the liquid and the vapour at the boiling point are 115 cm3 mol'1 and 14.5 dm3 mol' 1 , respectively. Estimate the change in the boiling point of the liquid at 180°C per bar change in atmospheric pressure, dT/dp using the Clayperon equation. Briefly discuss the physical significance of the sign of dT/dp .

In: Mechanical Engineering

Hibbeler said in Engineering Mechanics Statics page 167 (14th Edition): "Notice that FR is independent of...

Hibbeler said in Engineering Mechanics Statics page 167 (14th Edition):

"Notice that FR is independent of the location of point O since it's simply a summation of the forces"

What I want to ask, It's known that a couple moment is a free vector and it can be moved arbitrary to any point on the body but how can I insist the same concept for Resultant Force, although I can't assure that point O is on the line of the action of FR

In different words, how can I move FR freely while not the Principle of Transmissibility nor free vector is applied to it.

In: Mechanical Engineering

A hot silver plate is having its upper surface cooled by air forced convection of 15...

A hot silver plate is having its upper surface cooled by air forced convection of 15 °C with heat transfer coefficient of 220 W/m.K. The 10-cm thick plate (mass density ρ=8530 kg/m3, Cp=380J/kg.K, k=110 W/m.K, and α=33.9×10-6 m2/s) has a uniform initial temperature of 650 °C, and the bottom surface of the plate is insulated.

(a) calculate the Bi number and determine whether the lumped capacitance method can be used. (2 points)

(b) Determine the temperature at the center plane of the plate after 3 minutes of cooling. Solve this problem using the analytical one-term approximation method. (Hint: use table 5.1 in the lecture slides) (8 points)

In: Mechanical Engineering

3. (a) Among thin-film and emerging photovoltaic technologies, explain two photovoltaic cells you understand well, in...

3. (a) Among thin-film and emerging photovoltaic technologies, explain two photovoltaic cells you understand well, in terms of working principle, structure, materials used, fabrication techniques, advantages, and disadvantages.

(b) Assume you are about to start a business in photovoltaic technologies. Based on what you have studied in this course; what type of photovoltaic cell business would you like to run? Explain the reasons.

In: Mechanical Engineering

The air, which has a temperature of 120 ° C, flows over a plate with a...

The air, which has a temperature of 120 ° C, flows over a plate with a length of 1.2 m and a constant temperature of 30 ° C across the surface, and its speed flows at a speed of 2 m / s. According to this,
a.) Calculate the speed and temperature boundary layer thickness at the end of the plate.
b.) Find the local heat transfer coefficient and heat flux at the end of the plate.
c.) Find the average heat transfer coefficient and heat flux at the end of the plate.
(Properties of the air will be taken from the table)

all informations are given

In: Mechanical Engineering

Engineering Standards and Codes of Practice a) With reference to the Engineers Australia Guidelines on Professional...

Engineering Standards and Codes of Practice

a) With reference to the Engineers Australia Guidelines on Professional Conduct (part of their Code of Ethics), please write, in your own words, a concise summary of the requirements for competent practice

See Australia Guidelines on Professional Conduct below:

Engineers Australia

Our Code of Ethics

The Guidelines on Professional Conduct

The Guidelines on Professional Conduct provide a framework for members of Engineers Australia to use when exercising their judgment in the practice of engineering. The Guidelines are not intended to be, nor should they be interpreted as, a full or exhaustive list of the situations and circumstances which may comprise compliance and non-compliance with the Code of Ethics. If called upon to do so, members are expected to justify any departure from both the provisions and spirit of the Code. Ethical engineering practice requires judgment, interpretation and balanced decision-making in context. Engineers Australia recognises that, while our ethical values and principles are enduring, standards of acceptable conduct are not permanently fixed. Community standards and the requirements and aspirations of engineering practice will develop and change over time. Within limits, what constitutes acceptable conduct may also depend on the nature of individual circumstances. Allegations of non-compliance will be evaluated on a case-by-case basis and administered in accordance with Engineers Australia’s General Regulations 2013.

1. DEMONSTRATE INTEGRITY 1.1 Act on the basis of a well-informed conscience a) be discerning and do what you think is right b) act impartially and objectively c) act appropriately, and in a professional manner, when you perceive something to be wrong d) give due weight to all legal, contractual and employment obligations 1.2 Be honest and trustworthy a) accept, as well as give, honest and fair criticism b) be prepared to explain your work and reasoning c) give proper credit to those to whom proper credit is due d) in managing perceived conflicts of interest, ensure that those conflicts are disclosed to relevant parties e) respect confidentiality obligations, express or implied f) do not engage in fraudulent, corrupt, or criminal conduct 1.3 Respect the dignity of all persons a) treat others with courtesy and without discrimination or harassment b) apply knowledge and skills without bias in respect of race, religion, gender, age, sexual orientation, marital or family status, national origin, or mental or physical handicaps

2. PRACTISE COMPETENTLY 2.1 Maintain and develop knowledge and skills a) continue to develop relevant knowledge and expertise b) act in a careful and diligent manner c) seek peer review d) support the ongoing development of others 2.2 Represent areas of competence objectively a) practise within areas of competence b) neither falsify nor misrepresent qualifications, grades of membership, experience or prior responsibilities 2.3 Act on the basis of adequate knowledge a) practise in accordance with legal and statutory requirements, and with the commonly accepted standards of the day b) inform employers or clients if a task requires qualifications and experience outside your areas of competence

3. EXERCISE LEADERSHIP 3.1 Uphold the reputation and trustworthiness of the practice of engineering a) advocate and support the extension of ethical practice b) engage responsibly in public debate and deliberation 3.2 Support and encourage diversity a) select, and provide opportunities for, all engineering practitioners on the basis of merit b) promote diversity in engineering leadership 3.3 Communicate honestly and effectively, taking into account the reliance of others on engineering expertise a) provide clear and timely communications on issues such as engineering services, costs, outcomes and risks

4. PROMOTE SUSTAINABILITY 4.1 Engage responsibly with the community and other stakeholders a) be sensitive to public concerns b) inform employers or clients of the likely consequences of proposed activities on the community and the environment c) promote the involvement of all stakeholders and the community in decisions and processes that may impact upon them and the environment 4.2 Practise engineering to foster the health, safety and wellbeing of the community and the environment a) incorporate social, cultural, health, safety, environmental and economic considerations into the engineering task 4.3 Balance the needs of the present with the needs of future generations a) in identifying sustainable outcomes consider all options in terms of their economic, environmental and social consequences b) aim to deliver outcomes that do not compromise the ability of future life to enjoy the same or better environment, health, wellbeing and safety as currently enjoyed

Our Code of Ethics

As engineering practitioners, we use our knowledge and skills for the benefit of the community to create engineering solutions for a sustainable future. In doing so, we strive to serve the community ahead of other personal or sectional interests. Our Code of Ethics defines the values and principles that shape the decisions we make in engineering practice. The related Guidelines on Professional Conduct provide a framework for members of Engineers Australia to use when exercising their judgment in the practice of engineering. As members of Engineers Australia, we commit to practise in accordance with the Code of Ethics and accept that we will be held accountable for our conduct under Engineers Australia’s General Regulations 2013. In the course of engineering practice we will:

1. DEMONSTRATE INTEGRITY 1.1 Act on the basis of a wellinformed conscience 1.2 Be honest and trustworthy 1.3 Respect the dignity of all persons

2. PRACTISE COMPETENTLY 2.1 Maintain and develop knowledge and skills 2.2 Represent areas of competence objectively 2.3 Act on the basis of adequate knowledge

3. EXERCISE LEADERSHIP 3.1 Uphold the reputation and trustworthiness of the practice of engineering 3.2 Support and encourage diversity 3.3 Communicate honestly and effectively, taking into account the reliance of others on engineering expertise

4. PROMOTE SUSTAINABILITY 4.1 Engage responsibly with the community and other stakeholders 4.2 Practise engineering to foster the health, safety and wellbeing of the community and the environment 4.3 Balance the needs of the present with the needs of future generations

In: Mechanical Engineering

0.5 kg of air at 30 bar and 350 °C is allowed to expand reversibly in...

0.5 kg of air at 30 bar and 350 °C is allowed to expand reversibly in a cylinder behind a piston in such a way that the temperature remains constant to a pressure of 0.75 bar. Based on the law pv1.05= constant, the air is then compressed until the pressure is 10 bar. Assuming air to be a perfect gas, determine the:

a) net entropy change,
b) net heat flow,
c)net work energy transfer and sketch the processes on a T-s diagram, indicating the area, which represents the heat flow.

In: Mechanical Engineering

Hook gauge is a low cost that can detect a very small changes in liquid level...

Hook gauge is a low cost that can detect a very small changes in liquid level in open tank. A small changes in liquid will give a large change in metric. Which indirect liquid level measurement below is able to achieve the same output as hook gauge with a low cost? Briefly explain how the measurement works.
a) Capacitance level gauge
b) Hydrostatic pressure gauge
c) Bubbler
d) Ultrasonic level gauge

In: Mechanical Engineering

Water at 15°C enters a tube of 2 cm of diameter with flow rate 3953 kg/h....

Water at 15°C enters a tube of 2 cm of diameter with flow rate 3953 kg/h. Assume the ratio L/D >10, and the wall temperature is constant at 80◦C. The outlet temperature is 50°C The properties of water at the film temperature are density rho = ? = 985 ?/?3, specific heat ?p = 4180 ?/?, conductivity ? = 0.651 ?/?, dynamic viscosity mu= ?? = 4.71 × 10−4 ?/?, At the wall temperature of 80°C we have dynamic viscosity muw= ?? = 3.55 × 10−4?/?

1. Calculate the average velocity, ?

2. Calculate Reynolds number ?e?

3. Determine the flow regime

4. Calculate Prandtl number ?r

5. Calculate the rate of heat transfer, ?

6. Calculate the mean temperature ??

7. Calculate Nusselt number ?u?

8. Calculate convection heat transfer coefficient ℎ

9. Calculate the length of the tube ?

10. Calculate the ratio ?/D

In: Mechanical Engineering

A stainless steel (AISI 316) tube used to transport a chilled pharmaceutical has an inner diameter...

A stainless steel (AISI 316) tube used to transport a chilled pharmaceutical has an inner diameter of 30 mm and a wall thickness of 3 mm. The pharmaceutical and ambient air are at temperatures of 6oC and 23oC, respectively, while the corresponding inner and outer convection coefficients are 400 W/m2 K and 6 W/m2 K, respectively.
(a) What is the heat gain per unit tube length?
(b) What is the heat gain per unit length if a 10-mm thick layer of calcium silicate insulation (k = 0.050 W/m. K) is applied to the tube?

In: Mechanical Engineering

List and elaborates 5 advantages and disadvantages of hybrid engine for automotive application. Prepare a short...

List and elaborates 5 advantages and disadvantages of hybrid engine for automotive application. Prepare a short essay of your finding.

In: Mechanical Engineering

Check section W 14 X 132 for the column C1 subjected to the following loads Pu=...

Check section W 14 X 132 for the column C1 subjected to the following loads Pu= Mux= Muy= Let Lb = [ 10 ] ft (Base Plate) Then Design the Base Plate for the W-Shaped Column C1 consider the axial load only (ignore My & Mx). The column C1 section is [W 14X 132] and it is subjected to a factored axial compression load Pu= [280 + 6 ] kips. Assume concrete compressive strength 4 ksi , Fu (steel plate )=58 Ksi , fy=50 Let Lb = [ 10 ]

In: Mechanical Engineering

Air is expanded isentropically in an adiabatic turbine, to produce 135 kW of power. If the...

Air is expanded isentropically in an adiabatic turbine, to produce 135 kW of power. If the mass flow rate is 0.75 kg/s, and the air at the exit is 500 K and 305 kPa, then what is the temperature and pressure at the inlet of the turbine?

(a) The temperature is K.

(b) The pressure is kPa.

NOTE: Do NOT approximate the air as having a constant specific heat.

In: Mechanical Engineering

The following problem description applies also to the next two problems. A piston-cylinder device contains 2...

The following problem description applies also to the next two problems.

A piston-cylinder device contains 2 kg of a saturated liquid mixture at an initial state 1 with p1= 100 kPa and x1= 0.8. The water is heated at constant pressure until its final state 2 with volume V2 = 1.947V1.

Its initial volume, in m3/kg, is closer to:

Its final temperature, in oC, is closer to:

The amount of heat supplied to the steam during the expansion process, in kJ, is closer to:

In: Mechanical Engineering