Determine the radial acceleration of the ultracentrifuge using calculations
1 answer:
When something moves on a round track, the guidance of the something's velocity must continually switch. A switching velocity means that there must be an acceleration. This acceleration is horizontal to the guidance of the velocity. This is said as “the radial acceleration”, or “centripetal acceleration” ("centripetal" means "center searching"). The “radial acceleration” is equal to “the square of the velocity”, divided by “the radius of the circular path of the object”. The unit of the “centripetal acceleration” is m/s².
where,
"v" = "velocity" (m/s) and "r" = "radius of motion of the object" (m)
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The correct answer is
<span>C) either the pressure of the gas, the volume of the gas, or both, will increase.
In fact, the ideal gas law can be written as
</span>
<span>where
p is the gas pressure
V is its volume
n is the number of moles
R is the gas constant
T is the absolute temperature of the gas
We can see that if the temperature T increases, then the term on the right in the equation increases, therefore the term on the left should increase as well. In order for this to be possible, at least one between p and V should increase, or also both of them. Therefore, the correct answer is C.</span>
<span>C) either the pressure of the gas, the volume of the gas, or both, will increase.
In fact, the ideal gas law can be written as
</span>
<span>where
p is the gas pressure
V is its volume
n is the number of moles
R is the gas constant
T is the absolute temperature of the gas
We can see that if the temperature T increases, then the term on the right in the equation increases, therefore the term on the left should increase as well. In order for this to be possible, at least one between p and V should increase, or also both of them. Therefore, the correct answer is C.</span>
Answer:
A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.
Explanation:
Complete statement is: <em>Determine the power that needs to besupplied by the fan if the desired velocity is 0.05 cubic meters per second and the cross-sectional area is 20 square centimeters.</em>
From Thermodynamics and Fluid Mechanics we know that fans are devices that work at steady state which accelerate gases (i.e. air) with no changes in pressure. In this case, mechanical rotation energy is transformed into kinetic energy. If we include losses due to mechanical friction, the Principle of Energy Conservation presents the following equation:
(Eq. 1)
Where:
- Efficiency of fan, dimensionless.
- Electric power supplied fan, measured in watts.
- Rate of change of kinetic energy of air in time, measured in watts.
From definition of kinetic energy, the equation above is now expanded:
(Eq. 2)
Where:
- Density of air, measured in kilograms per cubic meter.
- Volume flow, measured in cubic meters per second.
- Cross-sectional area of fan, measured in square meters.
If we know that ,
,
and
, the power needed to be supplied by the fan is:
A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.