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2 years ago

3

A freeway exit ramp has a single lane and consists entirely of a horizontal curve with a central angle of 90 degrees and a lengt

h of 628 ft. If the distance cleared from the centerline for sight distance is 19.4 ft, what design speed was used?

1 answer:

Arte-miy333 [17]2 years ago

8 0

Answer:

umm lemme check it out

Explanation:hold on okay

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A ________ is only achieved through control and involves a specific change in one event (dependent variable) that can reliably b

prohojiy [21]

Answer:

Functional Relationship

Explanation:

A functional relationship is only achieved through control and involves a specific change in one event (dependent variable) that can reliably be produced by specific manipulations of another event (independent variable), and the change in the dependent variable is unlikely to be the result of other extraneous factors (confounding variables

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2 years ago

Technician A says that TSBs are typically updates to the owner's manual. Technician B says that TSBs are generally

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Answer:

Technician A says that TSBs are typically updates to the owner's manual. Technician B says that TSBs are generally

updated information on model changes that do not affect the technician. Who is correct? the answer is c

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2 years ago

A thin-walled tube with a diameter of 12 mm and length of 25 m is used to carry exhaust gas from a smoke stack to the laboratory

nlexa [21]

Answer:

(a) h₁ = 204.45 W/m²k

(b) h₀ = 46.80 W/m².k

(c) T = T = 15.50°C

Explanation:

Given Data;

Diameter = 12mm

Length = 25 m

Entry temperature = 200°C

Flow rate = 0.006 kg/s

velocity = 2.5 m/s.

Step 1: Calculating the mean temperature;

(200 + 15)/2

Mean temperature = 107.5°C = 380.5 K

The properties of air at mean temperature 380.5 K are given as:

v = 24.2689*10⁻⁶m²/s

a = 35.024*10⁻⁶m²/s

μ = 221.6 *10⁻⁷Ns/m²

k = 0.0323 W/m.k

Cp = 1012 J/kg.k

Step 2: Calculating the prantl number using the formula;

Pr = v/a

= 24.2689*10⁻⁶/ 35.024*10⁻⁶

= 0.693

Step3: Calculating the reynolds number using the formula;

Re = 4m/πDμ

= 4 *0.006/π*12*10⁻³ * 221.6 *10⁻⁷

= 0.024/8.355*10⁻⁷

= 28725

Since Re is greater than 2000, the flow is turbulent. Nu becomes;

Nu = 0.023Re^0.8 *Pr^0.3

Nu = 0.023 * 28725^0.8 * 0.693^0.3

= 75.955

(a) calculating the heat transfer coefficient:

Nu = hD/k

h = Nu *k/D

= (75.955 * 0.0323)/12*10^-3

h = 204.45 W/m²k

(b)

Properties of air at 15°C

v = 14.82 *10⁻⁶m²/s

k = 0.0253 W/m.k

a = 20.873 *10⁻⁶m²/s

Pr(outside) = v/a

= 14.82 *10⁻⁶/20.873 *10⁻⁶

= 0.71

Re(outside) = VD/v

= 2.5 * 12*10⁻³/14.82*10⁻⁶

=2024.29

Using Zakauskus correlation,

Nu = 0.26Re^0.6 * Pr^0.37 * (Pr(outside)/Pr)^1/4

= 0.26 * 2024.29^0.6 * 0.71^0.37 * (0.71/0.693)^1/4

= 22.199

Nu = h₀D/k

h₀ = Nu*k/D

= 22.199* 0.0253/12*10⁻³

h₀ = 46.80 W/m².k

(c)

Calculating the overall heat transfer coefficient using the formula;

1/U =1/h₁ +1/h₀

1/U = 1/204.45 + 1/46.80

1/U = 0.026259

U = 1/0.026259

U = 38.08

Calculating the temperature of the exhaust using the formula;

T -T₀/T₁-T₀ = e^-[uπDL/Cpm]

T - 15/200-15 = e^-[38.08*π*12*10⁻³*25/1012*0.006]

T - 15/185 = e^-5.911

T -15 = 185 * 0.002709

T = 15+0.50

T = 15.50°C

6 0

2 years ago

Two kilograms of oxygen fills the cylinder of a piston-cylinder assembly. The initial volume and pressure are 2 m3 and 1 bar, re

valentinak56 [21]

Answer: Heat transfer (Q) is 521 kJ.

Explanation: In the piston-cilinder assembly, we can suppose that the oxygen act as an ideal gas, so, it can be used the General Gas Equation:

PV= $\frac{m}{M}$ RT, where:

P is pressure;

V is volume;

m is mass;

M is molar mass;

R is a constant: R = 8.314. $10^{-5}$ m³bar.K⁻¹.mol⁻¹;

T is temperature;

Using this equation, find the intial temperature:

PV = $\frac{m}{M}$ RT

1.2 = $\frac{2}{16}$ .8.314. $10^{-5}$ .T

T = 1.924. $10^{5}$ K

To determine the final temperature, use Combined Gas Law:

$\frac{P_{i} . V_{i} }{T_{i} }$ = $\frac{P.V }{T}$ , in which, the left side of the equality is related to the initial values and the right side, to the final values.

As pressure is constant:

$\frac{V_{i} }{T_{i} } =\frac{V}{T}$

T = $\frac{V.T_{i} }{V_{i} }$

T = $\frac{4.1.924.10^{-5} }{2}$

T = 3.85. $10^{5}$ K

With the temperatures, calculate the heat transfer of the process:

Q = m.k.ΔT, where:

k is heat constant

ΔT = T - $T_{i}$

Q = m.k.ΔT

Q = 2.1.35.(3.85 - 1.92). $10^{5}$

Q = 521 kJ

The heat transfer in the process is 521 kJ.

6 0

2 years ago

Read 2 more answers

5. Which statement regarding a finite state machine (FSM) is NOT true: (a) In a non-deterministic FSM, a string is invalid if th

valkas [14]

Answer:

The statement (a) In a non-deterministic FSM, a string is invalid if there is one path not leading to a final state is NOT true

Explanation:

A non-deterministic FSM, contrary to deterministic FSM which has only one possible thread of execution, has multiple threads and for the machine to be invalid, all threads should lead to a none accepting (final) state.

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2 years ago