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course phy 202
I am really not sure why I am not understanding most of these. Could you please help me? I'm sorry it is not coming to me as easily as it should :/
Test Problems:
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Constants:
k = 9*10^9 N m^2 / C^2
qE = 1.6 * 10^-19 C
h = 6.63 * 10^-34 J s
energy of n=1 orbital in hydrogen atom: -13.6 eV
k ' = 9 * 10^-7 T m / amp
atomic mass unit: 1.66 * 10^-27 kg
electron mass: 9.11 * 10^-31 kg
speed of light: 3 * 10^8 m/s
Avogadro's Number: 6.023 * 10^-23 particles/mole
Gas Constant: R = 8.31 J / (mole K)
proton mass: 1.6726 * 10^-27 kg
neutron mass: 1.6749 * 10^-27 kg
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Problem Number 1
Use Bernoulli's equation to determine the velocity with which water will exit from a hole in a uniform cylinder when the cylinder is filled to a point 2.8 meters above the hole, assuming that the water in the cylinder moves with negligible velocity.
1000Kg/m^2*9.8m/s^2*(-3m)= -29400 N/m^2
-29400 N/m^2=29400 N/m^2
0.5 ‘rho v^2=29400 N/m^2
v=?? I get lost here
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You should know the density of water.
Substituting the density of water you can solve this equation for v.
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Problem Number 2
Analyze the pressure vs. volume of a 'bottle engine' consisting of 4 liters of an ideal gas as it operates between minimum temperature 200 Celsius and maximum temperature 330 Celsius, pumping water to half the maximum possible height. Sketch a pressure vs. volume graph from the original state to the maximum-temperature state and use the graph to determine the useful work done by the expansion. Then, assuming a monatomic gas, determine the thermal energy required to perform the work and the resulting practical efficiency of the process.
• University Physics Students: Analyze the entire process, assuming that after the maximum temperature is achieved pressure is suddenly released, resulting in an adiabatic expansion.
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.This problem does not even make sense to me at all
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This requires careful attention to class notes, as well as good work on the assigned experiments.
Do a thorough review of the assigned class notes, and be sure you have completed the experiments for Module 1 successfully.
Then use a question form to tell me what you do and do not understand about this situation, and we'll build from there.
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.Problem Number 4
How much steam at 100 C should we add to 80 grams of water at 20 C and 17 grams of ice at 0 C to end up with only water at 100 C, assuming that all thermal exchanges take place within this system?
Again, I am stuck…..
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Suppose you were to add 10 grams of steam.
Compare the energy given up by the steam if it all condenses to the energy required to raise the water and ice to 100 C.
Which is greater?
Now, what quantity of steam would be required to make the two results equal?
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Problem Number 5
What gauge pressure is necessary in a hose to spray water to a height of 13 meters?
Pressure = Density × Gravity acceleration × height
Density of water =1000Kg/m^-3
Gravity acceleration = 9.8m/s˛
Height = 13.0 m
P=1000kg/m^3*9.8m/s^2 * 13.0 m
=127400 Pa
=127 kPa
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Good.
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Problem Number 6
There is a small amount of water at the bottom of a sealed container of volume 8.7 liters which is otherwise full of an ideal gas. A thin tube open to the atmosphere extends down into the water, and up to a height of 229 cm. The system is initially at atmospheric pressure and temperature 148 Celsius.
• If we increase the temperature of the gas until water rises in the tube to a height of 164 cm, then what is the temperature at that instant?
Absolute Temp= 148+273= 421 K
P=164/229
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The ratio of water column heights is not equal to the ratio of the pressures.
The pressure added to raise the water must be added to atmospheric pressure to get an absolute pressure, and only the ratio of absolute pressures has any direct bearing here.
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=0.71
(0.71)*(306K)=
I am lost again…."
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You need to start by finding the pressures necessary to raise the water to heights of 229 cm and 164 cm.
Then you will need to find the corresponding temperatures.
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Check my notes. You know your additional questions are invited.
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