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KatRina [158]
4 years ago
11

A smoking lounge is to accommodate 19 heavy smokers. The minimum fresh air requirement for smoking lounges is specified to be 30

L/s per person (ASHRAE, Standard 62, 1989). Determine the minimum required flow rate of fresh air that needs to be supplied to the lounge and the diameter of the duct if the air velocity is not to exceed 8 m/s. (Round the final answers to two and three decimal places, respectively.) The minimum required flow rate of fresh air that needs to be supplied to the lounge is m3/s. The diameter of the duct if the air velocity is not to exceed 8 m/s is m.
Engineering
1 answer:
igor_vitrenko [27]4 years ago
7 0

Answer 1: minimum required flow rate of fresh air is 0.57 m^3/ses

Explanation: since the minimum requirement per person is 30 L/sec

Converting to m^3 it becomes

30/1000 = 0.03 m^3/sec

For 19 heavy smoker we will require

19 * 0.03 = 0.57m^3/sec

Answer 2: diameter of the duct will be 0.3m

Explanation: since flow rate is

Q =0.57m^3/sec

Also

Q = AV (continuity equation)

Where A is the duct area and V is the velocity of air flow in m/sec

0.57m^3/sec = A * 8m/sec

A = 0.57/8 = 0.071m^2

Area of the duct is that of a circle

A = 3.142 *(d^2 ÷4)

d^2 = (0.017 * 4)/3.142 = 0.09

d is square root of 0.09

d = 0.3m

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harina [27]

Answer:

Rack and Pinion Steering Rack and pinion steering transmits circular motion from the steering wheel to a pinion that meshes with teeth on a flat rack. ... Suspension Systems The suspension system supports the vehicle, allowing the wheels to move up and down over irregularities in the road.

3 0
3 years ago
Read 2 more answers
1.00-L insulated bottle is full of tea at 90.08°C. You pour out one cup of tea and immediately screw the stopper back on the bot
liberstina [14]

Answer:

T_{f} = 90.07998 ° C

Explanation:

This is a calorimetry process where the heat given by the Te is absorbed by the air at room temperature (T₀ = 25ºC) with a specific heat of 1,009 J / kg ºC, we assume that the amount of Tea in the cup is V₀ = 100 ml. The bottle being thermally insulated does not intervene in the process

                 Qc = -Qb

                M c_{e_Te} (T₁ -T_{f}) = m c_{e_air} (T_{f}-T₀)

Where M is the mass of Tea that remains after taking out the cup, the density of Te is the density of water plus the solids dissolved in them, the approximate values are from 1020 to 1200 kg / m³, for this calculation we use 1100 kg / m³

   ρ = m / V  

   V = 1000 -100 = 900 ml  

   V = 0.900 l (1 m3 / 1000 l) = 0.900 10⁻³ m³  

   V_air = 0.100 l = 0.1 10⁻³ m³  

Tea Mass  

     M = ρ V_te  

     M = 1100 0.9 10⁻³  

     M = 0.990 kg  

Air mass  

     m = ρ _air V_air  

     m = 1.225 0.1 10⁻³  

     m = 0.1225 10⁻³ kg  

(m c_{e_air} + M c_{e_Te}) T_{f}. = M c_{e_Te} T1 - m c_{e_air} T₀  

T_{f} = (M c_{e_Te} T₁ - m c_{e_air} T₀) / (m c_{e_air} + M c_{e_Te})  

Let's calculate  

T_{f} = (0.990 1100 90.08– 0.1225 10⁻³ 1.225 25) / (0.1225 10⁻³ 1.225 + 0.990 1100)  

T_{f} = (98097.12 -3.75 10⁻³) / (0.15 10⁻³ +1089)  

T_{f} = 98097.11 / 1089.0002  

T_{f} = 90.07998 ° C  

This temperature decrease is very small and cannot be measured

3 0
3 years ago
In a balanced Y-Y three-phase circuit 120 10 Van    V rms. The load impedance per phase is 20 15 ZZ j L Y    . Determine
ANEK [815]

Given Information:

Balanced Y-Y three phase circuit

Phase Voltage = Van = 120 < 10° V

Load Impedance = Zy = 20 +j15 Ω = 25 < 36.86° Ω

Required Information:

Load Voltages = Vab, Vbc, Vca = ?

Line currents = Ia, Ib, Ic = ?

Answer:

Vab = 208 < 40°

Vbc = 208 < -80°

Vca = 208 < 160°

Ia = 4.8 < -26.86°

Ib = 4.8 < -146.86°

Ic = 4.8 < 93.14°

Explanation:

Since it is balanced 3 phase system, all phases have equal magnitude and 120° phase shift

Van = 120 < 10° V

Vbn = 120 < -110° V

Vcn = 120 < 130° V

In a Y connected system, the phase voltage and line voltage are related as

Vab = \sqrt{3}(Van) <+30°

Vab = \sqrt{3}*120<10°+30°

Vab = 208 < 40°

Vbc = 208 < -80°

Vca = 208 < 160°

In a Y connected circuit, Iphase = Iline

Ia = Van/Zy

Ia = 120 < 10°/25 < 36.86°

Ia = 4.8 < -26.86°

Ib = 4.8 < -146.86°

Ic = 4.8 < 93.14°

7 0
4 years ago
The force exerted on a vane due to a jet of water is only a function of the mass flowrate and independent of the jet velocity. a
hoa [83]

Answer:

b) false

Explanation:

We know that rate of change of  momentum is called force.

So

Force = rate of change of momentum

F=\dfrac{dP}{dt}

We know that

P = m v

So

\dfrac{dP}{dt}=\dfrac{dm}{dt}V  (take velocity in constant and not changing with time)

F=\dfrac{dm}{dt}V

So F=\dot{m}V

So force exerted by jet depends on mass flow rate and velocity also.So our option b is right.

5 0
3 years ago
Later in this course we will learn how to combine flip-flops to make transitions to desired outputs. The flip-flop is holding bi
expeople1 [14]

Answer:

Clock input( or Timer Oscillator)   in used to change the state of the output.  

Explanation:

Flip-flop is an device that is the state changes with the rising or falling of the clock. It has a control signal (clock) input that stores the input state and outputs the state only in response to the clock signal.

The output changes with the change in the input in synchronization with the clock.  

Whenever the input of the clock changed, it will result in change in the output.

8 0
3 years ago
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