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Engineering

What's the difference between engineering stress and strain and true stress and strain

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Engineering

The value of the critical Reynolds number for the flow over a flat plate is 5 x10^5. The significance of the value is:

(a) The boundary layer will be turbulent where the Reynolds number is less than this value.

(b) At a position along the plate where the Reynolds number equals this value, transition from laminar to turbulent boundary layer gradually occurs.

(c) If the Reynolds number for the plate based on the length L is greater than this value, then the boundary layer is turbulent over the entire plate.

(d) Transition from laminar to turbulent boundary layer will occur immediately when this value is exceeded.

(e) None of the above represent a reasonable answer!

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Vanessa Reynolds

Engineering

Answer True of False to the following statements.

a. Above its glass transition temperature, a polymer is glassy and brittle.

b. Below the glass transition temperature, polymer chains lose their mobility (they are less capable of bending, flexing, raveling, and rotating about covalent bonds along the backbone.

c. The glass transition temperature of a material is normally above its melting temperature.

d. The elastic modulus of a polymer decreases when it is heated above its glass transition temperature

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Charles Bonilla

Engineering

A Carnot cycle is to be designed to attain

efficiency of 0.75. It temperature of the

reservoir is 727°C, then low temperature

reservoir will have to be maintained at °C

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Engineering

Where are environmental consultants employed?

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Engineering

Evaluate to three significant figures and using appropriate prefix: (354 mg) (45 km) / (0.0356 kN)

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Engineering

Two well-known NP-complete problems are 3-SAT and TSP, the traveling salesman problem. The 2-SAT problem is a SAT variant in which each clause contains at most two literals. 2-SAT is known to have a polynomial-time algorithm. Is each of the following statements true or false?

1. 3-SAT ≤p TSP. 2. If P ¹ NP, then 3-SAT ≤p 2-SAT. 3. If P ¹ NP, then no NP-complete problem can be solved in polynomial time.

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Engineering

Describe line and surface defects including edge, screw and mixed dislocations.

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Engineering

n a simple electric circuit, Ohm's law states that V=IR, where V is the voltage in Volts, I is the current in Amperes, and R is the resistance in Ohms. Assume that, as the battery wears out, the voltage decreases at 0.02 Volts per second and, as the resistor heats up, the resistance is increasing at 0.04 Ohms per second. When the resistance is 300 Ohms and the current is 0.02 Amperes, at what rate is the current changing?

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Engineering

On a hot summer day, a student turns his fan on when he leaves his room in the morning. When he returns in the eve - ning, will the room be warmer or cooler than the neighboring rooms?

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Engineering

3. Technician A says that on-board self-diagnostics test mode procedures should be conducted on a cold engine. Technician B says that many diagnostic trouble codes (DTCs) will monitor items only when the engine control system is in closed loop.

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Engineering

Mixing refrigerants can cause

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Camden Cisneros

Engineering

What is the thermal energy contained within a cubic kilometre of granite (in barrels of oil equivalent) for every one degree change in temperature? Use the following parameters in your calculation: Specific heat of granite = 790 (J/kgC) Density of granite = 2700 kg/m3 Energy in 1 barrel of oil = 6.118e9 J

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Engineering

Which benefits of a connected world makes all applications, equipment (such as a high-volume printer), and data available to anyone on the network, without regard to the physical location of the resource or the user?

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Engineering

Kirchhoff's junction law says that the total current into a junction must equal the total current leaving the junction.

a. True

b. False

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