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Ksenya-84 [330]

2 years ago

7

The equation 9(u – 2) + 1.5u = 8.25 models the total miles Michael traveled one afternoon while sledding, where u equals the num

ber of hours walking up a hill and (u – 2) equals the number of hours sledding down the hill. Which is the value of u?
A. u = 0.25
B. u = 0.75
C.u = 1.1
D. u = 2.5

2 answers:

earnstyle [38]2 years ago

8 0

The <u>equation </u> $9(u-2) + 1.5u = 8.25$ <u>models</u> the total miles Michael traveled one afternoon while sledding. u equals to <u>number of hours</u> walking up a hill and (u – 2) equals to number of hours sledding down the hill.

Solve this equation:

$9(u-2) + 1.5u = 8.25,\\ \\9u-18+1.5u=8.25,\\ \\9u+1.5u=8.25+18,\\ \\10.5u=26.25,\\ \\u=2.5\ hours$

Answer: correct choice is D

Greeley [361]2 years ago

4 0

D is the correct answer

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2 years ago

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$M=168k$

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Now we need to find the x-coordinate of the center of mass.

$\bar{x}=\frac{1}{M}\int\int x*\rho dydx$

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$\bar{x}=\frac{k}{168k}\int^{9}_{1}\int^{4}_{1}x*y^{2} dydx$

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$\bar{x}=\frac{21}{168}\frac{x^{2}}{2}|^{9}_{1}$

$\bar{x}=\frac{21}{168}*40=5$

Now we need to find the y-coordinate of the center of mass.

$\bar{y}=\frac{1}{M}\int\int y*\rho dydx$

$\bar{y}=\frac{1}{M}\int^{9}_{1}\int^{4}_{1}y*ky^{2} dydx$

$\bar{y}=\frac{k}{168k}\int^{9}_{1}\int^{4}_{1}y^{3} dydx$

$\bar{y}=\frac{1}{168}\int^{9}_{1}\frac{y^{4}}{4}|^{4}_{1}dx$

$\bar{y}=\frac{1}{168}\int^{9}_{1}\frac{255}{4}dx$

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$\bar{y}=\frac{255}{672}8=\frac{2040}{672}$

$\bar{y}=\frac{85}{28}$

Therefore the center of mass is:

$(\bar{x},\bar{y})=(5,\frac{85}{28})$

I hope it helps you!

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2 years ago

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1 year ago

Read 2 more answers

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AysviL [449]

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To better understand the solution, see attachment for the diagram.

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<CFE = 1/2(80)

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