Answer:
ω₂ = 93.6 rev / min
Explanation:
ω₀ = 260 rev / min
ω₁ = 0.68*ω₀ = 0.68*(260 rev / min) = 176.8 rev / min
ω₂ = ?
t₁ = 1 min
t₂ = 2 min
We can apply the equation:
ω₁ = ω₀ + α*t₁ ⇒ α = (ω₁ - ω₀) / t₁
⇒ α = (176.8 rev / min - 260 rev / min) / 1 min = - 83.2 rev / min²
then we can use the same formula, knowing the angular acceleration:
ω₂ = ω₀ + α*t₂ ⇒ ω₂ = (260 rev / min) + (- 83.2 rev / min²)*(2 min)
⇒ ω₂ = 93.6 rev / min
Answer:
False
Explanation:
(I guess if it were written "properly" it would be ax=bx implies a=b).
Given the axioms we were given, it would seem that the statement should be true, no?
A related statement -- also listed as false -- is that "in any vector space, ax=ay implies that x=y." Again, given the axioms we have.
C
because 40 j dived by 5 seconds is 8 work
Answer:
Explanation:
Let consider that pipe is a horizontal cylinder. The Nusselt number is equal to:
![Nu = \left\{0.6+\frac{0.387\cdot Ra_{D}^{\frac{1}{6} }}{[1+\left(\frac{0.559}{Pr} \right)^{\frac{9}{16}} ]^{\frac{8}{27} }} \right\}^{2}](https://tex.z-dn.net/?f=Nu%20%3D%20%5Cleft%5C%7B0.6%2B%5Cfrac%7B0.387%5Ccdot%20Ra_%7BD%7D%5E%7B%5Cfrac%7B1%7D%7B6%7D%20%7D%7D%7B%5B1%2B%5Cleft%28%5Cfrac%7B0.559%7D%7BPr%7D%20%20%5Cright%29%5E%7B%5Cfrac%7B9%7D%7B16%7D%7D%20%5D%5E%7B%5Cfrac%7B8%7D%7B27%7D%20%7D%7D%20%20%5Cright%5C%7D%5E%7B2%7D)
, for 
.
Where 
is the Rayleigh number associated with the cylinder.
The Rayleigh number is:
By assuming that air behaves ideally, the coefficient of volume expansion is:
The cinematic and dynamic viscosities, thermal conductivity and isobaric specific heat of air at 10 °C and 1 atm are:
The Prandtl number is:
Likewise, the Rayleigh number is:
Finally, the Nusselt number is:
![Nu = \left\{0.6+\frac{0.387\cdot (12.486\times 10^{6})^{\frac{1}{6} }}{\left[1 + \left(\frac{0.559}{0.733}\right)^{\frac{9}{16} }\right]^{\frac{8}{27} }} \right\}^{2}](https://tex.z-dn.net/?f=Nu%20%3D%20%5Cleft%5C%7B0.6%2B%5Cfrac%7B0.387%5Ccdot%20%2812.486%5Ctimes%2010%5E%7B6%7D%29%5E%7B%5Cfrac%7B1%7D%7B6%7D%20%7D%7D%7B%5Cleft%5B1%20%2B%20%5Cleft%28%5Cfrac%7B0.559%7D%7B0.733%7D%5Cright%29%5E%7B%5Cfrac%7B9%7D%7B16%7D%20%7D%5Cright%5D%5E%7B%5Cfrac%7B8%7D%7B27%7D%20%7D%7D%20%20%5Cright%5C%7D%5E%7B2%7D)
