A local elevator moves upward at a constant 3.3 mps passing a stopped express elevator. Precisely 2.8 seconds later the express elevator starts upward with a constant acceleration and catches up with the local elevator where the velocity of the local with respect to the express elevator is -9.3 m/s. Determine (a) the acceleration of the express elevator in m/s/s and (b) the distance traveled in m for the express to catch up with the local elevator.

q1) Fluid ( ρ = 850 kg/m³; μ = 0.08 Pa.s) flows through a 4-cm diameter tube at 0.5 m/s. The Reynolds number of the fluid is

q2 ) An oil with ρ= 900 kg/m³ and ν= 2x10^-4 m²/s flows upward through an inclined pipe of diameter 4 cm as shown in Fig. 1. The pressures at sections 1 and 2 (L =11.3 m apart) are p₁ = 359 kPa and p₂ = 201 kPa, respectively. Assuming steady laminar flow, compute the average velocity; in m/s.

q3) Fluid ( ρ = 850 kg/m³; μ = 0.08 Pa.s) flows through a 4-cm diameter tube at 50 m/s. The flow characterizes as:

Q4) The hydrodynamic entry length of laminar flow fluid ( S.G = 0.985 ; ν = 1.47x10^-5 m²/s) flowing through tube at 0.13 m/s is 27.6 cm. The tube diameter is:

Q) Fluid ( S.G = 0.985 ; ν = 1.47x10^-5 m²/s) flows through a 5-mm diameter tube at 3.3 m/s. The hydrodynamic entry length of this flow is:

Q6) Fluid ( S.G = 0.985 ; μ = 1.47x10^-2 Pa.s) flows through a 15-cm diameter tube at 3.3 m/s. The hydrodynamic entry length of this flow is:

When aging an aluminum alloy, the final hardness depends on time at the heat treatment temperature. The time to achieve peak age (maximum hardness):

Question 1

a) Determine the specific enthalpy of steam at 15 bar and 275°C .

b) Determine the degree of superheat and entropy of steam at 10 bar and 380 °C.

c) A superheated steam at 12.5 MN/m2 is at 650°C .Determine its specific volume.

Question 2

A superheated steam at 24 bar and 500 °C expands at constant volume until the pressure becomes 6 bar and the dryness fraction is 0.9. Calculate the changes in the internal energy of steam. Sketch the process in the form of a P-v diagram.

Question 3

Steam at 10 bar and 200 °C enters a convergent-divergent nozzle with a velocity of 60 m/s and leaves at 1.5 bar and with a velocity of 650 m/s. Assuming that there is no heat loss, determine the quality of steam leaving the nozzle.

Question 4

The temperature of feed water entering a boiler is 311 °C and steam is produced at 40 bar and 500 °C. The rate of heat transfer to the surroundings is 35 kW. Determine the mass flow rate of the working fluid for a heat input to the boiler of 6 MW.

Question 5

Exhaust steam from a turbine enters a condenser with a specific enthalpy of 2164 kJ/kg and a velocity of 75 m/s. During the cooling process, the heat loss to the cooling water per kg of working fluid is 1680 kJ/kg. The condensate exits the system with a velocity of 12 m/s. Sketch a systems diagram for the condenser and determine the specific enthalpy of the working fluid at exit from the condenser.

Question 6

A steady flow boiler is supplied with water at 15 kg/s, 100 bar pressure, and 200 °C. The water is heated and turned into steam. The steam leaves at 100 bar and 500 °C. Determine the heat transfer rate.  

A torsion test is performed on an aluminum probe, with the following results given in the following table:

The probe dimensions are as follows:

Length(L)

Diameter(D)

Through your graph of behavior of shear to torsion against angular deformation determine the following:

• Limit proportional to the cut

• Shear creep (0.2% deformation)

• Maximum resistance shear
• rigidity modulus (G)

• Cut Resilience Module

 Failure type (malleable, ductile, tenacious or brittle)

3. The compression ratio of the ideal air-powered diesel cycle is 14, while the cutting rate is 1.8.Since the air was initially at 100 kPa and 25 ° C;
a. Pressure and temperature at the end of the heat transfer process
b. Thermal efficiency
c. Find the mean effective pressure (M.E.P).

The radius of the impeller of a centrifugal pump at the inlet is 6 cm and at the outlet is 10.5 cm. The blade angles β1 and β2 are respectively 33o and 21o respectively. The width of the impeller is uniform and 4.75 cm. The impeller rotates at 1200 rpm and pumps water (See Figure 1). Assuming radial entry, (a) the flow rate through the pump (b) the theoretical head (c) the power required assuming an efficiency of 75%. (d) the theoretical pump curve (the H-Q equation) (e) If the pump diameter were increased by 10% and the speed dropped by 10%, what would be the new flow and theoretical head?

Indicate whether the following statements are true or false. Explain.

1. The specific enthalpy of an ideal gas is a function of temperature and pressure.
2. Air cannot be regarded as a pure substance.
3. Liquid alternatively referred to as compressed liquid because its pressure is less than atmospheric pressure.
4. The pressure and temperature are not dependently variable for a system contains a two-phase liquid–vapor mixture at equilibrium.

An expansion tank is a necessity in a chilled water cooling network because:

1. The network is a closed loop system
2. It allows for the variation in temperature of chilled water in the chilled water circuit
3. Both A & B
4. None of the above

Please answer in less than an hour :)

Can you explain and show how we get the Specific Cutting pressure in GPa if vertical force is 0.882 kN, feed rate is .0508 mm/rev, and depth of the cut is 1.8161 mm.  

Q2 Describe the following tools as used in
directional drilling.
I. Bent Sub and Positive Displacement Motor
II. Non‐Rotating Steerable Drilling Systems
III. Rotary Steering System
IV. Directional Bottom Hole Assemblies (BHA)
V. Whipstocks

10 cm of copper with square cross section of 1x1 cm exposed to 200 KN tension force
caused 15% permanent reduction in cross section area , if the fracture got on this point,
calculate the following:
1 – the ductility
2 – stress
3 – true stress
4- fracture stress

--fluid mechanics--

The diameter of the soap bubbles (d) formed by a bubble toy is thought to be a function of surface tension between the soap-water solution (σs), the pressure difference between inside the bubble and the environment (ΔP), the diameter of the circular wire frame (D), the dynamic viscosity (μ) and the density (ρ) of the soap-water solution.

a) How many dimensionless parameters arise from this configuration?

b) Is there an evident dimensionless parameter which can be found without any calculation? If yes, which parameter?

c) If two of the repeating variables are given as surface tension (σs ) and density (ρ), find the rest of the repeating variable or variables.

d) Find the dimensionless parameters (Pi numbers)

e) The model experiments the D=3 cm diameter wire frame submerged into soap-water solution whose surface tension (σs) is 0,025 N/m, is blown with an effective pressure of 20 mm water-column. Find the effective pressure that needs to be applied if the D=30 cm wire frame prototype will work at 30°C (σs = 0,02 N/m)