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aliina [53]
3 years ago
8

A closed, rigid tank fitted with a paddle wheel contains 2.0 kg of air, initially at 200oC, 1 bar. During an interval of 10 minu

tes, the paddle wheel transfers energy to the air at a rate of 1 kW. During this time interval, the air also receives energy by heat transfer at a rate of 0.5 kW. These are the only energy transfers. Assume the ideal gas model for the air, and no overall changes in kinetic or potential energy. Do not assume specific heats are constant. Determine the change in specific internal energy for the air, in kJ/kg, and the final temperature of the air, in oC.
Engineering
1 answer:
RUDIKE [14]3 years ago
8 0

Answer:

T=833.8 °C

Explanation:

Given that

m= 2 kg

T₁=200 °C

time ,t= 10 min = 600 s

Work input = 1 KW

Work input = 1 x 600 KJ=600 KJ

Heat input = 0.5 KW

Q= 05 x 600 = 300 KJ

Gas is ideal gas.

We know that for ideal gas internal energy change given as

ΔU= m Cv ΔT

For air Cv= 0.71 KJ/kgK

From first law of thermodynamics

Q  = ΔU +W

Heat input taken as positive and work in put taken as negative.

300 KJ = - 600 KJ + ΔU

ΔU = 900 KJ

ΔU= m Cv ΔT

900 KJ = 2 x 0.71 x (T- 200 )

T=833.8 °C

So the final temperature is T=833.8 °C

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Which statement about tensile stress is true? A. Forces that act perpendicular to the surface and pull an object apart exert a t
svp [43]

Answer:

A. Forces that act perpendicular to the surface and pull an object apart exert a tensile stress on the object.

Explanation:

Tensile stress is referred as a deforming force, in which force acts perpendicular to the surface and pull an object apart, attempting to elongate it.

The tensile stress is a type of normal stress, in which a perpendicular force creates the stress to an object’s surface.

Hence, the correct option is "A."

3 0
3 years ago
2. BCD uses 6 bits to represent a symbol. a) True b) False​
Goshia [24]

Answer:

true because BCD used 6 bits to represent a symbol .

Explanation:

mark me brainlist

4 0
2 years ago
how is friction losses in pipes reduced? a. decrease the pipe diameter b. increase the length of the pipes. c. decrease the leng
Citrus2011 [14]

Friction losses in pipes can be reduced by decreasing the length of the pipes, reducing the surface roughness of the pipes, and increasing the pipe diameter. Thus, options (c),(e), and (f) hold correct answers.

Friction loss is a measure of the amount of energy a piping system loses because flowing fluids meet resistance. As fluids flow through the pipes, they carry energy with them. Unfortunately, whenever there is resistance to the flow rate, it diverts fluids, and energy escapes. These opposing forces result in friction loss in pipes.

Friction loss in pipes can decrease the efficiency of the functions of pipes. These are a few ways by which friction loss in pipes can be reduced and the efficiency of the piping system can be boosted:

  • <u><em>Decrease the length of the pipes</em></u>: By decreasing pipe lengths and avoiding the use of sharp turns, fittings, and tees, whenever possible result in a more natural path for fluids to flow.
  • <u><em>Reduce the surface roughness of the pipes</em></u>:  By reducing the interior surface roughness of pipes, a smooth and clearer path is provided for liquids to flow.
  • <u><em>Increase the pipe diameter: </em></u>By widening the diameters of pipes, it is ensured that fluids squeeze through pipes easily.

You can learn more about friction losses at

brainly.com/question/13348561

#SPJ4

3 0
1 year ago
A manometer is used to measure the air pressure in a tanlc The fluid used has a specific gravity of 1.25, and the differentialhe
Alenkasestr [34]

Answer:

(a) 11.437 psia

(b) 13.963 psia

Explanation:

The pressure exerted by a fluid can be estimated by multiplying the density of the fluid, acceleration due to gravity and the depth of the fluid. To determine the fluid density, we have:

fluid density = specific gravity * density of water = 1.25 * 62.4 lbm/ft^3 = 78 lbm/ft^3

height = 28 in * (1 ft/12 in) = 2.33 ft

acceleration due to gravity = 32.174 ft/s^2

The change in pressure = fluid density*acceleration due to gravity*height = 78*32.174*(28/12) = 5855.668 lbm*ft/(s^2 * ft^2) = 5855.668 lbf/ft^2

The we convert from lbf/ft^2 to psi:

(5855.668/32.174)*0.00694 psi = 1.263 psi

(a) pressure = atmospheric pressure - change in pressure = 12.7 - 1.263 = 11.437 psia

(b) pressure = atmospheric pressure + change in pressure = 12.7 + 1.263 = 13.963 psia

8 0
3 years ago
19. What part of the engine is shown at point "A" in the above figure?
stepan [7]

Answer:

C. Four bolt main

Explanation:

I think.. :)

6 0
3 years ago
Read 2 more answers
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