Love all your videos, but I wish you did slightly more complicated Physics examples! I'm in college and your calculus videos were very relevant and taught me a lot! Your physics videos definitely helps reinforce my knowledge but the examples are often much simpler than ones I have to tackle in class/exams, etc.
You are very smart. I hope all lot of people learn from this video. I am in grade 10, doing physics 11 and I am trying to learn energy before the teacher gets to explain it. THANK YOU !!!!!
I feel like this learning is somehow better than the "progressive education" that my school district provides, 𝐞𝐥𝐞𝐯𝐞𝐧 𝐲𝐞𝐚𝐫𝐬 𝐚𝐟𝐭𝐞𝐫 𝐭𝐡𝐢𝐬 𝐬𝐮𝐩𝐞𝐫𝐢𝐨𝐫 𝐞𝐱𝐩𝐥𝐚𝐧𝐚𝐭𝐢𝐨𝐧 𝐰𝐚𝐬 𝐫𝐞𝐜𝐨𝐫𝐝𝐞𝐝
UNIVERSAL GALAXY Depends on your definition of tracher,,, if it is someone who can pass knowledge in clear way, than he is a teacher, oposite to some ppl working in schools.
+Lunar Moon The closest I have seen Sal come to a school teacher is probably when he has visited schools and answered questions from children during math classes. There are a few images like that on the Internet.
if all the students that actually learnt from this didn't go to class anymore all the teacher would have no class. this makes so much more sense than in the 1.5hr class i have
Another way to state the consequence of this approach is; whatever the shape of the path which the object takes on its journey, its speed at any particular height is always the same. It's a shame that friction messes things up but in the world idealised ice slopes and perfect roller coasters I think its a really fascinating outcome.
You have saved my life. My friend and I have been trying to figure this out all week (teacher isn't there sometimes, and when he is we have work or something) and we have a quarterly test tomorrow. Thank you so much!! :D
I have always found vector fields and graphs of polar coordinates to be incredibly beautiful. Vector fields have some very complex symmetric patterns, and polar graphs sometimes look almost like flowers.
I swear, ALL college professors should be required to watch Khanacademy and PatrickJMT's videos before every stepping foot into a classroom. Too many of those guys (while VERY intelligent) have forgotten, or never learned, how to "teach".
It depends on the temperature of air. The reason a pendulum loses energy is that it collides with air molecules. The extra kinetic that is given to all those molecules is represented as heat. To calculate this, you can assume a block is moving in one direction at constant velocity.Depending on the area of the face of the block, it's momentum, air temperature (average velocity of air molecules) and pressure(how many there are) it can be calculated how much heat is given to the environment.
@PeaceFighter2 I might be wrong, but calculate when the ball is at the peak of its trajectory (where the velocity is 0), and at that point find the distance of the peak from the ground (or bottom of cliff, where ever it's landing). With that you can calculate gravitational pot. energy. Then you can set initial potential energy + Kinetic energy equal to final potential + Kinetic energy and solve. At that point of energy you can use Energy = work = force x d and find distance. Force being mg.
@ninjaturtle205: Good Question. There is a force being applied to the box by the surface, because otherwise the box would fall straight through it. This is the "normal force" which is talked about earlier in the playlist. So the force accelerates the box, thus changing its velocity, but the work done by the surface is assumed to be negligible, so the kinetic energy doesn't change, which means that the velocity changes in direction only, but I'm not entirely sure why it's negligible.
Previously he said it's assumed to be 10m/(s)^2 just for the sake of easy calculations. Gravity, however, differs from place to place (even on earth)...places such as the north pole will be much different. But usually as a constant (the level of physics we're doing) we have the average of gravity as 9.81m/s^2, for simplicity sake.
For you problem with the box being dropped on the crazy slope, since velocity is a vector, wouldn't it's direction affect PE and KE? It's direction seems to be changing constantly too. So, do we just ignore direction?
What are you talking about? Potential energy and Kinetical energy are not always equal. Its the summ of Ep and Ek that stays constant. For example Ep+Ek = const.
I ALWAYS LOVE your videos, you speak well and have exceptional penmanship. BUT in the last few videos I have watched you are using a thicker font which makes everything hard to read, follow and understand.. PLEASE go back the the thinner font when writing so that it is easier to follow along and read!! Thanks
You should be more consistent giving your answers with the correct amount of digits; the answer in the first example isn't 100 J, it's 0,1 kJ because you gave the mass with only one digit, which really means that the mass can be anywhere from 0.5 kg to 1.4 kg (adds an uncertainty which must be accounted for in the answer). I know it seems pointless, but some teachers put a lot of weight on this.
Sorry if this is an unnecessary question however it has been bothering me. Since in a given condition (Ex. pendulum swings from Point A to Point B) some of the energy is lost to sound or air resistance. I asked a teacher if there is a constant that represents conversion of energy into sound, thermal, due to air resistance and was told that the knowledge was beyond high school physics. DOES ANYBODY KNOW THIS EQUATION THAT INCORPORATES THE CONVERSION OF KE or PE into heat, sound, etc/ the concept?
Uhhh... I found about 3 videos on RU-vid with over 100k Views that talked about the conservation of energy. This is bizarre. The law of energy conservation is by far the most important physical law. How are there not more videos on this?
I feel that it's actually not always true in the example of the object rolling down the hill as some of the GPE must have transferred to heat energy as well owing to the friction acting upon the object.
i just wanted to say thank-you for putting the time to make these videos for us. I think that you sound better than my physics teacher! lol and i laugh a bit at the little jokes you do xD and the shaky mouse sometimes (yes im weird) thanks again!
Question: Why would you use this formula if you could use V^2=Vi^2+2ax? V^2=0+2(9.8)10, V=14m/s Seems easier. Could You show me another example where it might make more sense to choose an energy formula instead of velocity?
can you explain the formula or P.E+K.E+U?. which is change on potential E and change in kinetic E added to change in internal energy? what does the internal energy change, and how to solve for it?
@PeaceFighter2 Since it asks when is potential energy same as kinematic energy you can form formula: 1/2mv^2=mgh now since we know the velocity upwards and mass we can solve h which is the height in which the energies are same. 1/2*4kg*40m/s^2=4kg*9.81m/s^2*h Since both sides have mass we can simply take it off leaving the calculation in form-> 1/2*40m/s^2=9.81m/s^2*h now to get h we will just divide the whole calculation with 9.81m/s^2 Damn out of space.
09:27 - This probably sounds stupid but you multiply both sides by 2 because it's x 1/2 right? Why didn't we do that in the first example though? It was just 1/2 m vsquared = 100J. and then 1/2 vsquared = 100J. Why was the mass insignificant then (because it was one) but not now?
A debate for the law of conservation of mass/ energy ,I watched a video about these laws in you tube and I asked to him : Hello professor , can I ask you a simple question : imagine if you put a quantity( amount) of water in a glass ( simple glass) , can you put this water in another glass ( I mean : to the extent of 100% of quantity of water ) , can you carry this amount of water( 100% of amount) in another glass ( to put all quantity of water in another glass( without losing any drop or molecule of water during the transportation) , can you do that ? I think If you would try it you wouldn't, if you do that then your law( or equation) would be correct. Same thing happens when water condenses, is impossible to transport( to be transported)all amount of water ( all molecules) during the cycle of condensation,( during the rain formation ),it mean : the matter is losing during the cycles verify the physics pls, Someone reply to me : You need to distinguish between water being left behind and disappearing completely. As you transfer water from one glass to another you leave some behind so the original glass is wet , none of the water actually "dissapears"- matter is conserved . Same with the water cycle,, some water evaporates from the sea, but most remain as sea, some condenses as clouds, but some will remain as vapor ( gas) , some of the cloud will fall as rain but some remains as cloud- and so on. It's all there all the time Another ( someone) replied to me : That's incredible difficult, but you should know that the water you put in the glass will not go away. All of the contents in the first glass of water cannot be destroyed and the water cannot create any more water. It may change state( physically to ice or water vapour) but none of it will vanish, so technically it is possible to do this transfer a, and the law of conservation of mass is still correct. My rocket 🚀 reply was : My intention was to say : after a cycle the matter isn't turning back( at the extent of 100% )( all quantity, all molecules ,) By the way that is happening to the energy too, not only the matter is not turning back,but even the energy isn't turning back too ( as the matter isn't turning back too, so even the law of conservation of energy is not correct, These laws are atheists's laws, they are trying to say : we are eternal ,but that is not true. We're losing, friend ,matter is losing ,energy is losing,( everything is disappearing vanishing ,is losing) Were separating from energy,that is my law, Question : why energy is separating from the matter ? For example : sun is losing energy( heat or light ) where is going this energy ?! Are you saying : the energy will turn back ,it will conserve back into the matter ?; I doubt on it When I say : energy is losing I mean : is disappearing( vanishing) from our dimension ( our world) I can say another thing : if you transfer an amount of energy to another object ( from a battery to another) ,this energy will lose ( vanish ,disappear) anyway ,even you can transfer all energy ( all enectrons ,all atoms) ,it will lose (vanish) again ,or disappear( by casuality, spontaneously) The meaning is : you( all of you ) can conserve nothing ,nothing can be conserved ,that is my law, For example : if you transfer energy from a battery to another battery ( from a power bank to a phone), the phone will lose its energy after four(teen) days ( even if you wouldn't use it ), with other words : energy will separate from matter( from battery), like the sun 's energy,it is separating from it( the sun). Everything is separating ,that's my law. I have made a post in f book about this case ,against atheists ,with simply words the point is : the matter and energy are joined together,question is : who joined them ( it) ?! For example : sun ,sun is made by energy and matter , the sun is losing energy ( heat , light ) , it mean : it was made by two things : energy and matter ,it was joined together ,question is : who joined together them ? There were a high intelligence energy who joined( welded ) them ,( God)
