Question 5(Multiple Choice Worth 2 points)

Which of the following is NOT a true statement about construction drawings?

Tems11 [23]

The answer is #4, "They are always drawn in pen. That is false, because what if they have to erase a part of their desing, then what?

3 0

2 years ago

What is the air change rate (ACH) for a 100 ft^2 (9.3 m^2) space with a 10 ft (3.0 m) ceiling and an airflow rate of 200 cfm (95

kakasveta [241]

Answer:

The ACH is 12/h

Solution:

As per the question:

Area of the space, $A_{s} = 100 ft^{2}$

Height of the given space, h = 10 ft

Air flow rate, $Q_{a} = 200 cfm$

Now, to find the Air Change Rate (ACH):

We calculate the Volume of the given space:

$V_{s} = A_{s}\times h = 100\times 10 = 1000 ft^{3}$

Now, the ACH per min:

= $\frac{V_{s}}{Q_{a}} = \frac{1000}{200} = 5/min$

Now, ACH per hour:

= $\frac{60}{5} = 12/h$

3 0

3 years ago

You want to know your grade in Computer Science, so write a program that continuously takes grades between 0 and 100 to standard

Margarita [4]

Answer:

The code is given below in python

# Code Block 1

count = 0 # count variable

total = 0 # total variable

enter = '' # input variable

while enter != 'stop':

enter = input('Enter a grade:' )

if enter != 'stop' and enter.isdigit():

total += int(enter) # add to total value

count = count + 1 # then to the count

print float(total) / count

# Code Block 2

numbers = []

while enter != 'stop':

enter = input('Enter a grade:' )

if enter != 'stop':

numbers.append(int(enter))

print sum(numbers) / float(len(numbers))

5 0

3 years ago

What is the difference between a job and a profession

Digiron [165]

Job is the activity performed in exchange for monetary value. It is often short-term and only done as a person requires money to live. A profession is a vocation based on specialized educational training. Jobs is a narrower concept and do not make a significant impact on a person's life or society

4 0

3 years ago

On a cold winter day, wind at 55 km/hr is blowing parallel to a 4-m high and 10-m long wall of a house. If the air outside is at

koban [17]

Answer:

16.21 kW

Explanation:

Solution

Given that,

The velocity of wind = 55 km/hr

The length of the wall L = 10m

The height of the wall w = 4m

The surface temperature at wall Ts = 12° C

Temperature of air T∞ = 5°C

Now,

The properties of the air at atm and average film temperature =( 12 + 5)/2 = 8.5°C, which is taken from the air table properties.

k= 0.02428 W/m°C

v= 1.413 *10 ^⁻5

Pr =0.7340

Now,

Recall Reynolds number when air flow parallel to 10 m side

[ 55 * 1000/3600) m/s (10 m)/1.413 *10^⁻5 m²/s

Rel =1.081 * 10⁷

This value is greater than Reynolds number.

The nusselt number is computed as follows:

Nu =hL/k

(0.037Rel^0.08 - 871)Pr^1/3

Nu =1.336 * 10 ^4

The heat transfer coefficient is

h = k/L Nu

= 0.2428 W/m°C /10 m (1.336 * 10 ^4)

h = 32.43 W/m°C

The heat transfer area of surface,

As = 40 m²

= ( 4 m) (10 m)

As = 40 m²

The rate of heat transfer is determined as follows:

Q = hAs( Ts - T∞)

= (32.43 W/m²°C) (40 m) (12 - 5)°C

=9081 W

Q = 9.08 kW

When the velocity is doubled,

let say V = 110km/hr

The Reynolds number is

Rel = VL/v

= [110 * 100/3600) m/s] (10 m)/ 1.413 *10^⁻5 m²/s

Rel = 2.163 * 10 ^7

This value is greater for critical Reynolds number

The nusselt number is computed as follows:

Nu =hL/k

(0.037Rel^0.08 - 871)Pr^1/3

[0.037 ( 2.163 * 10 ^7)^0.08 - 871] (0.7340)^1/3

Nu =2.344 * 10^4

The heat transfer coefficient is

h = k/L Nu

= 0.2428 W/m°C /10 m (2.384 * 10 ^4)

h= 57.88 W/m²°C

The heat transfer area of surface,

As = wL

= ( 10 m) (4 m)

As = 40 m²

he rate of heat transfer is determined as follows:

Q = hAs( Ts - T∞)

= (57.88 W/m²°C) (40 m²) (12 - 5)°C

= 16,207 W

= 16.21 kW

3 0

3 years ago