Last semester for Physics 1, I found you about half-way through and you helped me get a good grade. This semester in Physics 2 I'm going to watch your videos that go with my prof. lectures so I won't have to play catch up. You're doing good things! Thanks from an EE major at U of H.
@@MichelvanBiezen Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.12 kg/s, and it leaves at 0.7 MPa and 50°C. The refrigerant is cooled in the condenser to 24°C and 0.65 MPa, and it is throttled to 0.15 MPa. show the cycle on a T-s diagram with respect to saturation lines, and determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, (b) the isentropic efficiency of the compressor, and (c) the COP of the refrigerator when i solved the example i said that Q rejected=m(hv@0.15mpa-hafter throttling) and i didn't say (h entering compressor-h after throttling) as we know that it exits from evaporator saturated and enters compressor superheated due to heat transfer in connecting line and pressure drop
I like to remember this as HET (Heat/Energy/Temperature) “Much of thermodynamics deals with three closely related concepts: temperature, energy, and heat. Much of students’ difficulty with thermodynamics comes from confusing these three concepts with each other.” -D. V. Schroeder, Thermal Physics, Addison Wesley Longman, 2000 “Heat is defined as the form of energy that is transferred across a boundary by virtue of a temperature difference or temperature gradient. Implied in this definition is the very important fact that a body never contains heat, but that heat is identified as heat only as it crosses the boundary. Thus, heat is a transient phenomenon. If we consider the hot block of copper as a system and the cold water in the beaker as another system, we recognize that originally neither system contains any heat (they do contain energy, of course.) When the copper is placed in the water and the two are in thermal communication, heat is transferred from the copper to the water, until equilibrium of temperature is established. At that point we no longer have heat transfer, since there is no temperature difference. Neither of the systems contains any heat at the conclusion of the process. It also follows that heat is identified at the boundaries of the system, for heat is defined as energy being transferred across the system boundary.” -Thermodynamics, G. J. V. Wylen, John Wiley & Sons, 1960. Heat is a form of energy but not all energy is heat. In order for it to be heat in the truest thermodynamics sense, it must increase temperature. I admit it is a confusing concept, since thermal heat is often used for what really should be called thermal energy.
Dear Professor, As we know that after mixing two gases of different temperatures they achieve thermal equilibrium. Suppose there are two gases having different temperatures separate from each other. Now hypothetically one gas has an average speed of molecule 50 m/s and the other has a speed of molecule 30 m/s. after mixing the two gases they collide with each other now the lower speed molecules or the low-temperature molecules gain 50 m/s speed and the higher speed molecules gain 30 m/s speed as it is a perfectly elastic collision. So it seems higher-speed molecules gain lower speed and lower-speed molecules get higher speed but all molecules do not get the same average speed. So why do we say that they achieve the same speed in thermal equilibrium? Please reply sir... Love from India❤
Gas molecules (of different mass) do not gain the same speed when mixed. (Only if they have the same mass). Gas molecules will have speeds such that the kinetic energies of the gas molecules are the same. Off course there is a distribution of velocities according to the Boltzman equation, such that the root mean square velocities are the same.
The very careful editing in your videos is clearly visible, editing out the moments when you are writing something long just to not make it tedious and long is very much appreciable. It's your wife who does the editing, right?
Instead of relative hotness or coldness. What about temperature: Defines the "direction" of heat flow between two objects, would that be a sufficient description ?
He is good but I wish he would have just emphasized that Temperature is simply a scale of measure of kinetic energy for large degree of freedom systems.
By far the best physics lectures that I've seen. Thank you!
Last semester for Physics 1, I found you about half-way through and you helped me get a good grade. This semester in Physics 2 I'm going to watch your videos that go with my prof. lectures so I won't have to play catch up. You're doing good things! Thanks from an EE major at U of H.
I'm Brazilian and I can understand better watching your videos than taking classes at college!
Thank you sir!
Welcome to the channel! Glad these videos are helping.
LOL. Me too, Thanks
I'm from brazil too
@@MichelvanBiezen Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at
0.14 MPa and -10°C at a rate of 0.12 kg/s, and it leaves at 0.7 MPa and 50°C. The
refrigerant is cooled in the condenser to 24°C and 0.65 MPa, and it is throttled to
0.15 MPa. show the cycle on a T-s diagram with respect to
saturation lines, and determine (a) the rate of heat removal from the refrigerated
space and the power input to the compressor, (b) the isentropic efficiency of the
compressor, and (c) the COP of the refrigerator when i solved the example i said that Q rejected=m(hv@0.15mpa-hafter throttling) and i didn't say (h entering compressor-h after throttling) as we know that it exits from evaporator saturated and enters compressor superheated due to heat transfer in connecting line and pressure drop
I love your format, I love your style, I love the fact that you constantly save my grades, and I love your bowties.
I like to remember this as HET (Heat/Energy/Temperature)
“Much of thermodynamics deals with three closely related concepts: temperature, energy, and heat. Much of students’ difficulty with thermodynamics comes from confusing these three concepts with each other.” -D. V. Schroeder, Thermal Physics, Addison Wesley Longman, 2000
“Heat is defined as the form of energy that is transferred across a boundary by virtue of a temperature difference or temperature gradient. Implied in this definition is the very important fact that a body never contains heat, but that heat is identified as heat only as it crosses the boundary. Thus, heat is a transient phenomenon. If we consider the hot block of copper as a system and the cold water in the beaker as another system, we recognize that originally neither system contains any heat (they do contain energy, of course.) When the copper is placed in the water and the two are in thermal communication, heat is transferred from the copper to the water, until equilibrium of temperature is established. At that point we no longer have heat transfer, since there is no temperature difference. Neither of the systems contains any heat at the conclusion of the process. It also follows that heat is identified at the boundaries of the system, for heat is defined as energy being transferred across the system boundary.” -Thermodynamics, G. J. V. Wylen, John Wiley & Sons, 1960.
Heat is a form of energy but not all energy is heat. In order for it to be heat in the truest thermodynamics sense, it must increase temperature. I admit it is a confusing concept, since thermal heat is often used for what really should be called thermal energy.
thank you very much, sir! I'm in the 1st year of high school, struggling a lot with physics. Your videos have helped me a lot
Happy to help!
Dear Professor,
As we know that after mixing two gases of different temperatures they achieve thermal equilibrium.
Suppose there are two gases having different temperatures separate from each other. Now hypothetically one gas has an average speed of molecule 50 m/s and the other has a speed of molecule 30 m/s.
after mixing the two gases they collide with each other now the lower speed molecules or the low-temperature molecules gain 50 m/s speed and the higher speed molecules gain 30 m/s speed as it is a perfectly elastic collision. So it seems higher-speed molecules gain lower speed and lower-speed molecules get higher speed but all molecules do not get the same average speed. So why do we say that they achieve the same speed in thermal equilibrium?
Please reply sir...
Love from India❤
Gas molecules (of different mass) do not gain the same speed when mixed. (Only if they have the same mass). Gas molecules will have speeds such that the kinetic energies of the gas molecules are the same. Off course there is a distribution of velocities according to the Boltzman equation, such that the root mean square velocities are the same.
The very careful editing in your videos is clearly visible, editing out the moments when you are writing something long just to not make it tedious and long is very much appreciable.
It's your wife who does the editing, right?
Yes, she does all the behind the scenes work. She is the best!
Thank you Michel Van Biezen for your help!
sir I have a question that you said temperature is the. hotness or coldness of a body so how heat influence the temperature
When you add heat (energy) to an object, the temperature of the object will go up.
Instead of relative hotness or coldness. What about temperature:
Defines the "direction" of heat flow between two objects, would that be a sufficient description ?
Not exactly. It is very difficult to define.
Holy fucking shit, this guy is awesome. There's everything here. Thanks, man!
u r a boss...
thank you for this video.
Michel van Biezen I think this thermodynamics playlist has a problem with the order of the video. Please fix it professor. Thank you
He is good but I wish he would have just emphasized that Temperature is simply a scale of measure of kinetic energy for large degree of freedom systems.
Sir I am not getting the sequence of the topics..
Are you referring to the sequence of the physics playlists (chapters)?
👍
sir can you explain binomial theorem
It is a means to easily and quickly calculate the coefficients of the expansion of a binomial (like (a + b)) raised to an exponent.
hi, thank you really for video, can i contact you in privit? if yes please tell me where!, thank you sir befort
You can send a private message on this channel via youtube.
This lecture leaves something to be desired.
Has inaccuracies that promote disinformation.
I recommend to view other lectures as well.
Can you let me know what you think is inaccurate? (You indicated that there are multiple things wrong in this video).
Thank you 🌹and...Read more
You're welcome 😊
🙂
Glad you liked it.
@@MichelvanBiezen :)
"Heat is a form of energy"... and What is "Energy"? Try to explain.. ;-)
Sumit Tewari
The concept of :"heat" is explained in the physics videos on thermodymics
there is a meme thermometer is speedometer of atoms