All categories

3 years ago

Construction lines are thick lines true false

Engineering

2 answers:

n200080 [17]3 years ago

5 0

True hope this helps

ANTONII [103]3 years ago

4 0

Answer:

true

Explanation:

You might be interested in

Atmospheric air at 25 °C and 8 m/s flows over both surfaces of an isothermal (179C) flat plate that is 2.75m long. Determine the

vekshin1

Answer:

Re=100,000⇒Q=275.25 $\frac{W}{m^2}$

Re=500,000⇒Q=1,757.77 $\frac{W}{m^2}$

Re=1,000,000⇒Q=3060.36 $\frac{W}{m^2}$

Explanation:

Given:

For air $T_∞$ =25°C ,V=8 m/s

For surface $T_s$ =179°C

L=2.75 m ,b=3 m

We know that for flat plate

$Re$ ⇒Laminar flow

$Re>30\times10^5$ ⇒Turbulent flow

Take Re=100,000:

So this is case of laminar flow

$Nu=0.664Re^{\frac{1}{2}}Pr^{\frac{1}{3}}$

From standard air property table at 25°C

Pr= is 0.71 ,K=26.24 $\times 10^{-3}$

So $Nu=0.664\times 100,000^{\frac{1}{2}}\times 0.71^{\frac{1}{3}}$

Nu=187.32 ( $\dfrac{hL}{K_{air}}$ )

187.32= $\dfrac{h\times2.75}{26.24\times 10^{-3}}$

⇒h=1.78 $\frac{W}{m^2-K}$

heat transfer rate =h $(T_∞-T_s)$

=275.25 $\frac{W}{m^2}$

Take Re=500,000:

So this is case of turbulent flow

$Nu=0.037Re^{\frac{4}{5}}Pr^{\frac{1}{3}}$

$Nu=0.037\times 500,000^{\frac{4}{5}}\times 0.71^{\frac{1}{3}}$

Nu=1196.18 ⇒h=11.14 $\frac{W}{m^2-K}$

heat transfer rate =h $(T_∞-T_s)$

=11.14(179-25)

= 1,757.77 $\frac{W}{m^2}$

Take Re=1,000,000:

So this is case of turbulent flow

$Nu=0.037Re^{\frac{4}{5}}Pr^{\frac{1}{3}}$

$Nu=0.037\times 1,000,000^{\frac{4}{5}}\times 0.71^{\frac{1}{3}}$

Nu=2082.6 ⇒h=19.87 $\frac{W}{m^2-K}$

heat transfer rate =h $(T_∞-T_s)$

=19.87(179-25)

= 3060.36 $\frac{W}{m^2}$

7 0

3 years ago

An astronaut weighs 125 lbs on the surface of the Earth. What would she weigh in lbs if she is resting in the space shuttle that

alina1380 [7]

Answer:

weight of astronaut $F_2 = 113.38 lb$

Explanation:

Given data:

astronaut weight is = 125 lbs

distance of shuttle from surface of earth is 200 mils

we know that $F = G \frac{m_1 m_2}{r^2}$

where G, m_1, m_2 are constant value, so we have

$\frac{F_1}{F_2} = \frac{r_2^2}{r_1^2}$

radius of earth is 4000 miles

where r_2 = 4000 + 200 = 4200 miles

$\frac{125}{F_2} = \frac{4200^2}{4000^2}$

$F_2 = 113.38 lb$

3 0

3 years ago

A beaker is filled to the 500 ml mark with alcohol. What increase in volume (in ml) the beaker contain when the temperature chan

Tomtit [17]

Answer:

1.4 mL

Explanation:

Given that:

volume of alcohol $V_0$ = 500

Temperature change ΔT = (30° - 5°)C

=25° C

$\beta_{ alcohol }= 1.12 \times 10^{-4} / ^0C$

The increase in volume ΔV = $\alpha \times V_o \times \Delta T$

$= 500 \times 1.12 \times 10^{-4} / ^0 C\times 25^0 C$

= 1.4 mL

8 0

3 years ago

Everyone has only one learning style. True or false? hurry pleasle this exp carees class

Temka [501]

Answer:

This is False because people can have more than 1

7 0

3 years ago

Why are today’s homes more likely to have dangerous levels of carbon monoxide than older homes?

Margarita [4]

Answer:

Carbon monoxide has no odor, color or taste,so it cannot be detected by our senses. This means that dangerous concentrations of the gas can build up indoors and humans have no way to detect the problem until they become ill.

4 0

3 years ago