Stars are born within the clouds of dust and scattered throughout most galaxies. Deep within these clouds, turbulence creates knots with enough mass to cause the gas and dust to collapse under its own gravitational force.

4 0

3 years ago

A pin fin of uniform, cross-sectional area is fabricated of an aluminum alloy (k = 160 W/m-K). The fin diameter is D = 4 mm, and

frozen [14]

Answer:

Given that

D= 4 mm

K = 160 W/m-K

h=h = 220 W/m²-K

ηf = 0.65

We know that

$m=\sqrt{\dfrac{hP}{KA}}$

For circular fin

$m=\sqrt{\dfrac{4h}{KD}}$

$m=\sqrt{\dfrac{4\times 220}{160\times 0.004}}$

m = 37.08

$\eta_f=\dfrac{tanhmL}{mL}$

$0.65=\dfrac{tanh37.08L}{37.08L}$

By solving above equation we get

L= 36.18 mm

The effectiveness for circular fin given as

$\varepsilon =\dfrac{2\ tanhmL}{\sqrt{\dfrac{hD}{K}}}$

$\varepsilon =\dfrac{2\ tanh(37.08\times 0.03618)}{\sqrt{\dfrac{220\times 0.004}{160}}}$

ε = 23.52

5 0

2 years ago

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In a pendulum system, when is it possible for the potential and kinetic energies both to be equal to zero

muminat

That's ONLY true when the pendulum is hanging
in the center position and not moving.

8 0

3 years ago

A student makes a model of the sun-Earth system by swinging a ball around her head. Using this model, the student is trying to e

DedPeter [7]

Answer:

c. gravitational attraction between the sun and earth

8 0

3 years ago

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