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3 years ago

Ignore swell and shrinkage for this problem.

Engineering

1 answer:

Komok [63]3 years ago

6 0

Answer:

(a) 5.3

(b) 6

Explanation:

First we calculate time required for excavator to fill 1 truck:

Time to Fill 1 Truck = (No. of Cycles To Fill)(Cycle Time)

Time to Fill 1 Truck = (3)(33 sec)

Time to Fill 1 Truck = 99 sec

Now, we find the time taken by a truck to come back to excavator, after dumping:

Time of Return = Hauling Time + Time to Dump + Time to Come Back

Time of Return = 5 min + 45 sec + 3 min

Time of Return = 300 sec + 45 sec + 180 sec

Time of Return = 525 sec

(a)

In order to balance the output of excavator with number of trucks, following condition must be satisfied:

Time of Return = (No. of Trucks)(Time to Fill 1 Truck)

525 sec = (No. of Trucks)(99 sec)

No. of Trucks = 525 sec/99 sec

No. of Trucks = 5.3

(b)

If we round up the number of trucks, we get:

No. of Trucks = 6

(c)

If we round down the number of trucks, we get:

No. of Trucks = 5

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Disc brake rotors that are too thin cannot handle as much heat and will experience ___________.

konstantin123 [22]

Answer:

brake fade

Explanation:

Among the most frequent problems in the brake disc is their overheating. When there is overheating, the temperature of the disc rises to critical values, thus the brake pad starts to slide with respect to the disc, and the efficiency of the brake system decreases to a minimum.

Overheating of the brake disc is detected when inspecting the parts. Steel is the most common base material in the creation of brake discs. When heated, the material becomes its color. A disc of steel at critical temperature, turns bright orange and later on cooling becomes purple.

If a color change is seen on the brake discs when inspecting, a service station must be contacted without delay for an in-depth examination. After detecting the problem, the brake discs and pads will be changed in a mandatory way.

6 0

3 years ago

A 10-mm steel drill rod was heat-treated and ground. The measured hardness was found to be 290 Brinell. Estimate the endurance s

grandymaker [24]

Answer:

the endurance strength $S_e$ = 421.24 MPa

Explanation:

From the given information; The objective is to estimate the endurance strength, Se, in MPa .

To do that; let's for see the expression that shows the relationship between the ultimate tensile strength and Brinell hardness number .

It is expressed as:

$200 \leq H_B \leq 450$

$S_{ut} = 3.41 H_B$

where;

$H_B$ = Brinell hardness number

$S_{ut}$ = Ultimate tensile strength

From ;

$S_{ut} = 3.41 H_B$ ; replace 290 for $H_B$ ; we have

$S_{ut} = 3.41 (290)$

$S_{ut} =$ 988.9 MPa

We can see that the derived value for the ultimate tensile strength when the Brinell harness number = 290 is less than 1400 MPa ( i.e it is 988.9 MPa)

So; we can say

$S_{ut} < 1400$

The Endurance limit can be represented by the formula:

$S_e ' = 0.5 S_{ut}$

$S_e ' = 0.5 (988.9)$

$S_e '$ = 494.45 MPa

Using Table 6.2 for parameter for Marin Surface modification factor. The value for a and b are derived; which are :

a = 1.58

b = -0.085

The value of the surface factor can be calculate by using the equation

$k_a = aS^b_{ut}$

$K_a = 1.58 (988.9)^{-0.085$

$K_a = 0.8792$

The formula that is used to determine the value of $k_b$ for the rotating shaft of size factor d = 10 mm is as follows:

$k_b = 1.24d^{-0.107}$

$k_b = 1.24(10)^{-0.107}$

$k_b = 0.969$

Finally; the the endurance strength, Se, in MPa if the rod is used in rotating bending is determined by using the expression;

$S_e =k_ak_b S' _e$

$S_e$ = 0.8792×0.969×494.45

$S_e$ = 421.24 MPa

Thus; the endurance strength $S_e$ = 421.24 MPa

8 0

2 years ago

What is the maximum number of 12-2 with ground nonmetallic-sheathed cables permitted in an 18-cubic-inch device box if two singl

Novosadov [1.4K]

Answer:i think it is 35

Explanation:

i just guessed sorry im only in 5th grade

8 0

2 years ago

Read 2 more answers

A piston–cylinder device containing carbon dioxide gas undergoes an isobaric process from 15 psia and 80°F to 170°F. Determine t

drek231 [11]

Answer:

See explanation

Explanation:

Given:

Initial pressure,

psia

Initial temperature,

∘

Final temperature,

200

∘

Find the gas constant and specific heat for carbon dioxide from the Properties Table of Ideal Gases.

0.04513

Btu/lbm.R

0.158

Btu/lbm.R

Find the work done during the isobaric process.

−

(

−

)

(

−

)

0.04513

(

200

−

)

−

5.4156

Btu/lbm

Find the change in internal energy during process.

−

(

−

)

0.158

(

200

−

)

18.96

Btu/lbm

Find the heat transfer during the process using the first law of thermodynamics.

−

5.4156

18.96

−

24.38

Btu/lbm

7 0

2 years ago

Consider a very long, slender rod. One end of the rod is attached to a base surface maintained at Tb, while the surface of the r

9966 [12]

Answer:

(a) Calculate the rod base temperature (°C). = 299.86°C

(b) Determine the rod length (mm) for the case where the ratio of the heat transfer from a finite length fin to the heat transfer from a very long fin under the same conditions is 99 percent. = 0.4325m

Explanation:

see attached file below

3 0

3 years ago