In a curved channel, what causes the asymmetry in the full flow speed profile?
In: Mechanical Engineering
What is the basis of “Design for Maintainability”? When might the principles of Design for Maintainability lead to bad designs when followed without consideration of other principles? Defend your answer with a short example.
In: Mechanical Engineering
During a test a rocket travels upward at 75 meters/second, and when it is 40 meters from the ground its engine fails. Determine the maximum height h reached by the rocket and its speed just before it hits the ground. While in motion the rocket is subjected to a constant downward acceleration of 9.81 m/s2 due to gravity. Neglect the effect of air resistance.
In: Mechanical Engineering
Air enters a window air conditioner at 1 atm, 36oC and 75% relative humidity (??) at a rate of 12m3/min and it leaves as saturated air at 18oC. Part of the moisture in the air which condenses during the process is also removed at 18oC. Determine (a) the rate of heat (Q?) and (b) moisture removal from the air. (c) What-if Scenario: What would the rate of heat removal be if moist air entered the dehumidifier at 95 kPa instead of 1 atm?
In: Mechanical Engineering
Air at 28 °C, 1 bar, 50% relative humidity enters an insulated chamber operating at steady state with a mass flow rate of 5 kg/min and mixes with a saturated moist air stream entering at 4 °C, 1 bar with a mass flow rate of 8 kg/min. A single mixed stream exits at 1 bar. Determine
(a) the relative humidity and temperature, in °C, of the exiting stream.
In: Mechanical Engineering
Five kilograms of steam contained in a 2-m3 cylinder at 40 kPa is compressed isentropically to 5000 kPa. What is the work needed?
Please show correct work.
Answer: 185 kJ
In: Mechanical Engineering
16. List the two elements involved in preparing for maintenance on heat exchangers.
21. List two methods of cleaning the outside surfaces of tubes in a large shell- and-tube heat exchanger
26. Name the four types of plugs used in shell-and-tube heat exchangers to seal leaking tubes
28. Why is maintenance of a smaller heat exchanger done more easily in the shop?
In: Mechanical Engineering
Consider an airplane modeled after the twin-engine Beechcraft Queen Air executive transport. The airplane has the following characteristics: weight is 38,220 N; wing area is 27.3 m2; aspect ratio is 7.5; Oswald efficiency factor is 0.9; and zero-lift drag coefficient CD,0 is 0.03.
1) Calculate the thrust required to fly at a velocity of 725 km/h at standard sea level. Assume the value of ?? = 1.225 kg/m3 at standard sea level. (Round the final answer to the nearest whole number.) The thrust required to fly at a velocity of 725 km/h at standard sea level is _______N.
2) Calculate the thrust required to fly with a velocity of 725 km/h at an altitude of 4.5 km. Assume the value of ?? = 0.777 kg/m3 at an altitude of 4.5 km. (Round the final answer to the nearest whole number.) The thrust required to fly with a velocity of 725 km/h at an altitude of 4.5 km is _______ N.
In: Mechanical Engineering
What is Film blowing?
Describe the lost foam casting process. What is an advantage to lost foam casting?
How is most wrought steel initially produced?
Subject is actually Materials Science/Engineering
In: Mechanical Engineering
What is anthropometry? What are typical measures of anthropometry? What equipment is used? What does the equipment tell us? Why is anthropometry important to study? What is ergonomics?
In: Mechanical Engineering
What is external flow? What is internal flow? What is the Reynolds number? What is its physical interpretation? What are turbulent and laminar flows? Plot the variation of the local heat transfer coefficient for flow over a flat plate
In: Mechanical Engineering
What is the basis of Reynolds Analogy? (what is analogous to what?)
In: Mechanical Engineering
What is components? What is phases? What is tie line?
In: Mechanical Engineering
Class 20 and class 60 gray cast irons have tensile strengths of
about 20 ksi and
60 ksi, respectively. Assuming that the fractures start from
graphite flakes and that
the flakes act as preexisting cracks, use the concepts of the
Griffith analysis to predict
the ratio of the average graphite flake sizes of the two cast
irons.
In: Mechanical Engineering
1. You want to design a pendulum for a grandfather clock so that it has a period of 2.00 seconds (so that one “tick” plus one “tock” occur during one complete period). The pendulum has a heavy 8.00-kg bob. (Throughout this problem, assume an ideal simple pendulum: the pendulum’s arm has negligible mass, the bob can be approximated as a point-mass, the initial angle of displacement is small, and there is negligible friction.)
a.) If you want the clock to be used on the surface of the Earth near sea level (where g = 9.80 m/s2 ), what length should you use for the pendulum arm? Show your work. (Note: How many significant figures should your final answer have? Watch your rounding!)
b.) Suppose that the temperature in the room gets much warmer, and the length of the pendulum’s arm expands by 2.50%. By what percentage will the pendulum’s period increase? Show your work. Express your final answer as either a decimal factor or a percentage (with appropriate sig. figs.).
c.) Which one or more of the following changes would (when considered separately and individually) increase the period of the pendulum, thereby making the clock run “slower”? Circle ALL that apply:
A. moving the pendulum to the top of a (fictitiously) high mountain where g = 9.70 m/s2
B. sticking some putty on the pendulum bob, thereby increasing its mass
C. decreasing the amplitude of the pendulum’s swings
In: Mechanical Engineering