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dezoksy [38]
3 years ago
13

The primary heat transfer mechanism that quickly warms my hand if I hold it directly above a campfire is: a)-Radiation b)-Induct

ance c)- Convection d)- Conduction
Engineering
1 answer:
Tanzania [10]3 years ago
6 0

Answer:

The correct answer is option 'c':Convection.

Explanation:

When we ignite a campfire the heat produced by combustion heats the air above the fire. As we know that if a gases gains heat it expands thus it's density decreases and hence it rises, if we hold our hands directly above the fire this rising hot air comes in contact with our hands thus warming them.

The situation is different if we are at some distance from the campfire laterally. Since the rising air cannot move laterally the only means the heat of the fire reaches our body is radiation.

But in the given situation the correct answer is convection.  

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Name two common fuel gases that can be used for oxyfuel cutting
zlopas [31]
Hi

Acetylene and propane

I hope this help you!
8 0
1 year ago
2. The moist weight of 0.1 ft3 of soil is 12.2 lb. If the moisture content is 12% and the specific gravity of soil solids is 2.7
adell [148]

The answers to dry unit weight, void ratio, porosity, degree of saturation, volume occupied by water are respectively;

γ_d = 108.93 lb/ft³; e = 0.56; n = 0.36; S = 0.58; V_w = 0.021 ft³

<h3>Calculation of Volume and Weight of soil</h3>

We are given;

Moist weight; W = 12.2 lb

Volume of moist soil; V = 0.1 ft³

moisture content; w = 12% = 0.12

Specific gravity of soil solids; G_s = 2.72

A) Formula for dry unit weight is;

γ_d = γ/(1 + w)

where γ_w is moist unit weight as;

γ_w = W/V

γ_w = 122/0.1 = 122 lb/ft³

Thus;

γ_d = 122/(1 + 0.12)

γ_d = 108.93 lb/ft³

B) Formula for void ratio is;

e = [(G_s * γ_w)/γ_d] - 1

e = [(2.72 * 122)/108.93] - 1

e = 0.56

C) Formula for porosity is;

n = e/(1 + e)

n = 0.56/(1 + 0.56)

n = 0.36

D) Formula for degree of saturation is;

S = (w * G_s)/e

S = (0.12 * 2.72)/0.56

S = 0.58

E) Volume occupied by water is gotten from;

V_w = S*V_v

where;

V_v is volume of voids = nV

V_v = 0.36*0.1

V_v = 0.036 ft³

Thus;

V_w = 0.58 * 0.036

V_w = 0.021 ft³

Read more about Specific Gravity of Soil at; brainly.com/question/14932758

4 0
2 years ago
A 75-kg piano is hosted on a crane and delivered throughout the window of a 6th story apartment (20 meters above ground). What i
Sonja [21]

Answer:

  14,700 J

Explanation:

PE = Mgh = (75 kg)(9.8 m/s²)(20 m) = 14,700 J

8 0
3 years ago
Which of these physical concepts is most important in civil engineering?
mezya [45]

Answer:

Option A (energy transformations) is the correct solution.

Explanation:

  • Energy has become a local matter that has been primarily described as the commitment to deal as well as to generate heat. There are several other power sources, which can either be transferred or transformed to several other renewable technologies.  
  • This same fundamental law defined that the energy required including its universe has been corrected and therefore that energy is being generated as well as severely damaged but should only be moved from one location to the next.

Those certain possibilities are not connected to the circumstance in question. And therefore this answer seems to be the correct one.

3 0
3 years ago
water at 20c discharges from a stroke tank through a 150m length of horizontal pipe. The pipe is smooth and has a diameter of 75
inessss [21]

Answer:

The dept of the water needed is 26.11m

Explanation:

Given the following parameters:

Length of the pipe = 150m

Diameter of the pipe = 75mm = 0.75m

Volumetric flow rate 1m^{3}/s

Knowing that:

Volumetric flowrate = area (A) * Velocity(V)

==> 0.1 = A*V                              *Knowing that V = \sqrt{2gh}

==> 0.1  = \frac{\pi }{4}* (0.075)^{2} * \sqrt{2gh}

==> h = 26.11m

Hence, the dept of water needed to produce a volumetric flow rate of 1m^{3}/s is 26.11m.

7 0
3 years ago
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