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3 years ago

An unknown substance has a mass of 15 g and a volume of 4 cm3. Calculate the density of the unknown substance.

Physics

1 answer:

myrzilka [38]3 years ago

5 0

Answer:

Density is 3.75g/cm3

Explanation:

Density = mass ÷ volume

= 15g ÷ 4cm3

= 3.75g/cm3

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Two sites are being considered for wind power generation. In the first site, the wind blows steadily at 7 m/s for 3000 hours per

slavikrds [6]

Answer:

E.year₂ > E.year₁ (Second site is better)

Explanation:

Given data

$V_{1}=7 m/s\\Time_{1}=3000 hours/year\\V_{2}=10m/s\\Time_{2}=1500hours/year$

The power generation is the time rate of kinetic energy which can be calculated as:

Power=ΔKE=m×V²/2

Regarding that m ∝ V.Then

Power ∝ V³ ⇒ Power=constant×V³

Since ρa is constant for both sides and Area is the same as same wind turbine is used

For First site

$Power_{1}=const.V^3\\Power_{1}=const.(7m/s)^3\\Power_{1}=const.343Watt\\$

For second site

$Power_{2}=const.V_{2}^3\\Power_{2}=const.(10m/s)^3\\Power_{2}=const.1000W$

Calculating energy generation per year for each of two sites

E.year=Power×Operation time per year

For First site

E.year₁=Power₁×Operation time₁ per year

$E_{year1}=const.*343W*3000\\E_{year1}=const.1029000(W.hour/year)$

For Second site

E.year₂=Power₂×Operation time₂ per year

$E_{year2}=const.*1000W*1500\\E_{year2}=const.1500000(W.hour/year)$

E.year₂ > E.year₁ (Second site is better)

3 0

3 years ago

Read 2 more answers

A 150-newton force, applied to a wooden crate at an angle of 30° above the horizontal, causes the crate to travel at constant ve

koban [17]

Answer is in the photo. I can't attach it here, but I uploaded it to a file hosting. link below! Good Luck!

tinyurl.com/wtjfavyw

4 0

3 years ago

Identify the sentence that clearly states its meaning.

netineya [11]

<span>d) While taking a shower, I saw a little mouse scurry across the bathroom floor.

This sentence is ordered properly. </span>

7 0

3 years ago

In addition to stand-alone discussion boards, all of these sites include discussion boards as part of their features except:

adell [148]

Answer:

A. Linkedln

Explanation:

In addition to stand-alone discussion boards, all of these sites include discussion boards as part of their features except:

A. Linkedln

All other application in addition to stand-alone Google, Yahoo, Microsoft, etc. include discussion board.

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3 years ago

Determine the ratio of the flow rate through capillary tubes A and B (that is, QA/QB). The length of A is twice that of B, and t

Jet001 [13]

Answer:

$\dfrac{Q_A}{Q_B}=0.031$

Explanation:

Lets take

Radius of tube A=r

Length of tube A=L

Radius of tube B= r'

Length of tube B=L'

Given that

L = 2 L'

r= 0.5 r'

r' = 2 r

The pressure across tube given as

$\Delta p=\dfrac{8\mu LQ}{\pi R^{4}}$

$\dfrac{L_AQ_A}{ R_A^{4}}=\dfrac{L_BQ_B}{ R_B^{4}}$

$\dfrac{Q_A}{Q_B}=\dfrac{R_A^4}{R_B^4}\times \dfrac{L_B}{L_A}$

$\dfrac{Q_A}{Q_B}=\dfrac{r^4}{(2r)^4}\times \dfrac{L'}{2L'}$

$\dfrac{Q_A}{Q_B}=\dfrac{1}{16}\times \dfrac{1}{2}$

$\dfrac{Q_A}{Q_B}=0.031$

7 0

3 years ago