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2 years ago

A driver on a leveltwo-lane highway observes a

Engineering

1 answer:

NARA [144]2 years ago

3 0

Answer:

SSD = 565.54 ft

Explanation:

Given data:

driver speed = 60 mph

clear distance available to stop the truck on emergency can be calculated by using stopping sight distance

SSD = Lag distance + breaking distance

$SSD = vt + \frac{v^2}{2gf}$

let take comfortable acceleration rate as a = 11.2 ft/s^2

g =32.2 ft/s^2

a = fg

$f = \frac{11.2}{32.2} = 0.348$

speed is given as 60 mph

we know that 1 mile 5290 ft

i hr = 3600 sec

therefore v = 88 ft./s

from standard assumption time to reaction is taken as 2.5 sec

so $SSD = 88 \times 2.5 + \frac{88^2}{2\times 32.3\times 0.348}$

SSD = 565.54 ft

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A 0.19-m3 rigid tank equipped with a pressure regulator contains steam at 2 MPa and 300°C. The steam in the tank is now heated.

AVprozaik [17]

Answer:

576.21kJ

Explanation:

#We know that:

The balance mass $m_{in}+m_{out}=\bigtriangleup m_{system}$

so, $m_e=m_1-m_2$

$Energy \ Balance\\E_{in}-E_{out}=\bigtriangleup E_{system}\\\\\therefore Q_i_n+m_eh_e=m_2u_2-m_1u_1$

#Also, given the properties of water as;

$(P_1=2Mpa,T_1=300\textdegree C)->v_1=0.12551m^3/kg,u_1=2773.2kJ/kg->h_1=3024.2kJ/kg\\\\(P_2=2Mpa,T_1=500\textdegree C)->v_2=0.17568m^3/kg,u_1=3116.9kJ/kg->h_1=3468.3kJ/kg$

#We assume constant properties for the steam at average temperatures: $h_e=\approx(h_1+h_2)/2$

#Replace known values in the equation above; $h_e=(3024.2+3468.3)/2=3246.25kJ/kg\\\\m_1=V_1/v_1=0.19m^3/(0.12551m^3/kg)=1.5138kg\\\\m_2=V_2/v_2=0.19m^3/(0.17568m^3/kg)=1.0815kg$

#Using the mass and energy balance relations;

$m_e=m_1-m_2\\\\m_e=1.5138-1.0815\\\\m_e=0.4323kg$

#We have $Q_i_n+m_eh_e=m_2u_2-m_1u_1$ : we replace the known values in the equation as;

$Q_i_n+m_eh_e=m_2u_2-m_1u_1\\\\Q_i_n=0.4323kg\times3246.2kJ/kg+1.0815kg\times3116.9-1.5138kg\times2773.2kJ/kg\\\\Q_i_n=573.21kJ$

#Hence,the amount of heat transferred when the steam temperature reaches 500°C is 576.21kJ

5 0

3 years ago

Need help solving math problem using integration

notka56 [123]

Ummm did you try to add or subtract and multiply or divide that can get your answer

8 0

2 years ago

A heat pump operates on a vapor-compression refrigeration cycle with R-134a as the working fluid. The refrigerant enters the com

Rudiy27

Answer:

Hello your question has some missing information below are the missing information

The refrigerant enters the compressor as saturated vapor at 140kPa Determine The coefficient of performance of this heat pump

answer : 2.49

Explanation:

For vapor-compression refrigeration cycle

P1 = P4 ; P1 = 140 kPa

P2( pressure at inlet ) = P3 ( pressure at outlet ) ; P2 = 800 kPa

<u>From pressure table of R 134a refrigerant</u>

h1 ( enthalpy of saturated vapor at 140kPa ) = 239.16 kJ/kg

h2 ( enthalpy of saturated liquid at P2 = 800 kPa and t = 60°C )

= 296.8kJ/kg

h3 ( enthalpy of saturated liquid at P3 = 800 kPa ) = 95.47 kJ/kg

also h4 = 95.47 kJ/kg

To determine the coefficient of performance

Cop = ( h1 - h4 ) / ( h2 - h1 )

∴ Cop = 2.49

3 0

3 years ago

A 4140 steel shaft, heat-treated to a minimum yield strength of 100 ksi, has a diameter of 1 7/16 in. The shaft rotates at 600 r

velikii [3]

Answer:

Explanation:

4140-40 I’d pick wood

I hope this helps! :)

4 0

3 years ago

Read 2 more answers

Why is using the proper joining technique important? What could go wrong if the wrong joining technique is used?

Alex73 [517]

Answer:

Explanation:

Using the proper technique is incredibly important because it prevents the materials being joined from breaking and/or causing an accident. If the wrong joining technique is used the materials may not hold in place and come apart easily instead. Also, some joining techniques are not meant for some materials and may instead cause the material to become weak and brittle causing it to break apart almost immediately.

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3 years ago