Respuesta :
Answer:
2
Explanation:
To find the solution we must first make the transformations to international units,
In this way:
[tex]260cy / hr * 27ft ^ 3 / cy = 7020 ft ^ 3 / hr[/tex]
Inches of length (L) to feet =
[tex]7in * ft / 12in = 0.588ft[/tex]
So we can identify the area by hour:
[tex]A / h = 7020 / 0.588 = 12034.28 ft ^ 3 / hr[/tex]
Once the area is identified, we now identify the number of passes required,
Passes required = Area x number of passes
[tex]P_{r} = 12034.28 * 4[/tex]
[tex]P_{r} = 48136ft ^ 2 / hr[/tex]
We transform speed to international units
[tex]V = 2mph * 5280ft / mi[/tex]
[tex]V = 10560ft / hr[/tex]
So we can identify the covered area
[tex]covered_ {area} = v * m * p[/tex]
where
m = drum widht
p = efficiency
[tex]covered_{area} = 10560 * 4.16 * (55/60) = 40269ft ^ 2[/tex]
In this way we obtain the number of rollers given by:
No. of Rollers = Passes required / covered area
No of rollers = 48136/40269
No of rollers = 1.19, that is, 2.
Number of rollers required are 2.
The number of rollers would be as follows:
[tex]2[/tex]
Operating Efficiency
Given that,
Weight [tex]= 105 lb/cf[/tex]
Impacted weight [tex]= 122 lb/cf[/tex]
Rate [tex]= 260 cy/hr[/tex]
So,
[tex]260cy/hr[/tex] × [tex]27 ft^3/cy = 7020 ft^3/hr[/tex]
Thickness of layers [tex]= 7 in[/tex]
Now,
Inches can be turned into Length [tex]= 7in[/tex] × [tex]ft/12in = 0.588 ft[/tex]
Width of the roller drum [tex]= 4.16 ft[/tex]
Speed [tex]= 2 mph[/tex]
Operating efficiency [tex]= 55 min.[/tex]
So,
Area through the hour
[tex]A/h = 7020/0.588 \\= 12034.28 ft^3/hr[/tex]
Now,
No. of passes needed = Area × Number of passes
[tex]P_{r}[/tex] [tex]= 12034.28[/tex] × [tex]4[/tex]
[tex]= 48136 ft^2/hr[/tex]
Now,
∵ Speed [tex]= 2mph[/tex] × [tex]5280 ft/mi[/tex]
[tex]= 10560 ft/hr[/tex]
The covered area [tex]= vmp[/tex]
where
m [tex]=[/tex] width of the drum
p [tex]=[/tex] efficiency
[tex]= 10560[/tex] × [tex]4.16[/tex] × [tex](55/60)[/tex]
[tex]= 40269 ft^2[/tex]
The number of rollers can be determined by:
∵ No. of Rollers [tex]= Passes required / covered area[/tex]
[tex]= 48136/40269[/tex]
[tex]= 1.19[/tex] i.e. could be considered as [tex]2.[/tex]
Thus, [tex]2[/tex] is the correct answer.
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