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Gelneren [198K]
3 years ago
5

A homeowner purchases insulation for her attic rated at R-15. She wants the attic insulated to R-30. If the insulation she purch

ased is 10 cm thick, what thickness does she need to use
Physics
1 answer:
allochka39001 [22]3 years ago
4 0

Answer:

she need to use 20 cm thick

Explanation:

given data

wants the attic insulated = R-30

purchased = 10 cm thick

solution

as per given we can say that

10 cm is for the R 15

but she want for R 30

so  

R 30 thickness = \frac{30}{15} \times 10  

R 30 thickness = 20 cm

so she need to use 20 cm thick

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Answer:

Explanation:

Important here is to know that due north is a 90 degree angle, due east is a 0 degree angle, and due south is a 270 degree angle. Then we find the x and y components of each part of this journey using the sin and cos of the angles multiplied by each magnitude:

A_x=100cos90\\A_x=0\\B_x=55cos0\\B_x=55\\C_x=12cos270\\C_x=55

Add them all together to get the x component of the resultant vector, V:

V_x=55

Do the same to find the y components of the part of this journey:

A_y=100sin90\\A_y=100\\B_y=55sin0\\B_y=0\\C_y=12sin270\\C_y=-12

Add them together to get the y component of the resultant vector, V:

V_y=88

One thing of import to note is that both of these components are positive, so the resultant angle lies in QI.

We find the final magnitude:

V_{mag}=\sqrt{55^2+88^2} and, rounding to 2 sig dig's as needed:

V_{mag}= 1.0 × 10² m; now for the direction:

\theta=tan^{-1}(\frac{88}{55})= 58°

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Allushta [10]

Answer:

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Explanation:

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3 years ago
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