for some reason, you tube stops me from responding to some comments which are listed as "linked comment". But to answer the question about what is a level, A-levels are exams taken by students in the UK and elsewhere when they are aged 17-18 the results of which usually determine whether they can go on to study at university.
You're the best DrPhysicsA , you have helped me alot in understanding classical mechanics which has made my life very much easier. Keep doing what you love
Wow, these videos are so great. I don't study this in school, nor will this physics stuff ever benefit me but I still watch these videos cause they are so damn entertaining.
Thank you sooo much doctor! I started my A2 revision 2 months before everyone/school and your videos are like my teacher and they are amazing. Thanks again.
Balanced speed and clear intonation make this perfect delivery easy to understand! I am over 40 by the way and enjoying your teaching! Surely I will recommend your videos to my 10th grade son. Thank you sir!
True. I think that at the time I referred to t I hadn't introduced the concept of the period T so I used the general t for time. On the loop the loop - good point. Didn't think of that. Hope its not too confusing for the students. I'm minded of Leonard Susskind's videos where he sometimes finds himself using the same letter in an equation for two different purposes.
Superb Work sir, I am an avid lover of physics, and thanks to your channel, I can supplicate it with wealthy knowledge you share, absolutely amazing. - a Secondary School student admirer from Manchester.
Thank you for the excellent explanation 🙏 Circular motion is one of the most difficult to understand topic within A-Level syllabus , when differential calculus is not a pre-requisite !
If this is an experimental result it is probably because the string twists around the knife before it is cut. But the theoretical position is that if you cut the string then the ball will fly off tangentially.
Because once we have established the acceleration at a specific point and shown that it does not change we have determined centripetal acceleration for the entire cycle.
These videos look so amazing! Hopefully I can take a level physics next year in college, if so, i'm going to be using these video A LOT. Thank you so much in advance! :D
What we are saying is that if we swing the bucket at the frequency of 1 cycle every 2 seconds then the gravitational force will match the centripetal force needed to keep the water in the bucket. If we swing faster we make it even more likely that the water stays in the bucket. Any slower and water falls faster than the bucket and therefore falls out of the bucket.
I am using the principle, set out in more detail in a separate video on the manipulation of vectors. In order to find the difference between two vectors, you set them tail to tail and then the difference is the vector representing the distance between the two tips. For a constant speed, the vectors have the same length but they change direction. Since they have the same length, you can construct a circle where the vector length represents the radius. The arc length represents the difference.
I'll put it on the list. But the key point about 2D momentum is that momentum is conserved along both the x and y axis. This means that you have to calculate the component of the velocities in each direction.
Yes they are. Its just that f is the number of cycles (or full circles in your case) per second, while w (omega) is the number of radians swept out per second. Since there are 2 pi radians in one full circle w = 2 pi f
For the purposes of this question, all we need to do is to equate the gravitational force mg with the centripetal force mv^r/2. There will of course be a force between the car and the rail. This is sometimes called the centrifugal force. In practice, of course, it is simply the result of Newton's first law where the car is seeking to travel in a straight line but is compelled to follow the track in a circle. That force and the equal and opposite reaction force are not needed in this problem.
what you explained is awesome. very nice. But sir, I think, while explaining the loop the loop problem, you could have talked about the pseudo Centrifugal force here (although, both of the centripetal and centrifugal forces have the same magnitude) because it has just the opposite direction of action w.r.t the centripetal one and then we can equate that to the weight (mg) which is acting down . Thank you sir. Your explanation was too beautiful to watch.
The height of h in the roller coaster, if kept 2.5a, then as some energy does get converted to heat and sound energy, it wont even just stay but will fall off.......although the whole explanation cleared all my doubts about centripetal force and acceleration. Thank you +DrPhysicsA for the awesome explanation.
darun guru darun .A+ video . I want it to get 10000000000 likes and 1million $ . keep it up . keep helping weak students like us . Thanks........... Don Icy Rhymez.
Yes indeed. I think I say that you would in practice have to build in some spare capacity. But as you say, I doubt any such rides rely entirely on this kind of approach, not least in case the car gets stuck when it is upside down.
You can work out the orbital speed of the earth more easily than I did by saying that the earth completes one revolution (2πr) in 1 year. The radius is about 93 million miles. Convert a year to hours and then circumference/time will give you the solution in miles per hour. I think it comes to about 67,000 miles per hour which is equivalent to 30km/sec.
Hello Doc. Another great job and others thanks from me to you. Two small comments if i may : - I should have used the letter T (instead of t) when you defined the velocity, (v=2 pi R/t) because this time t is, as you said, the duration of the journey of one cycle, it's then the period T by definition. - In your loop the loop example, i should have used another letter than a for the radius of the loop just to avoid the confusion with the acceleration you just defined before.
Any chance you could cover some questions from the OCR G485/G484 syllabus. Some past paper questions would be stellar; your explanations are very precise.
I love this channel, Physics is my first career choice for university (I am in my 2nd year of high school) and so I'm participating in a competition to see if I really like it, and man your videos are fantastic, they are very well explained, thank you. (My second choice would be biochemistry)
At 0:30 I also thought that the motion of the earth around the sun is governed by Kepler's Laws...and it has an elliptical orbit...so..it has a minor and a major axis as well..moreover...the one part of the orbit is closer to the sun and so the earth gets a little bit accelerated here....thanks..man...I really love the way you teach physics.. b.t.w. I am from India under ICSE board...
When you were doing the loop the loop problem, where did you get F = (mu^2) / (a) from? Thanks for the help teach. edit: Ahh I see. So a = v^2 / r. So we place that for a in F=ma.
Hi Firstly your videos are if great help. Thank you for that secondly i have a question there seems to be so maby formulas how is possible to get my head around all of them....
Thank you sir a lot for your time to teach. We need more people like you but if I can give a light criticism please never use a as radius it is so darn confusing. I keep reminding myself all the time that that is radius and not acceleration :)
Good video! This is an invitation to see an artist theory on the physics of light & time. Based on: 1. The quantum wave particle function Ψ or probability function represents the forward passage of time itself with the future unfolding photon by photon. 2. Is that Heisenberg’s Uncertainty Principle ∆×∆p×≥h/4π that is formed by the w-function is the same uncertainty we have with any future event within our own ref-frame that we can interact with turning the possible into the actual!
Also i should have mentionned that , in the loop the loop example, friction forces were disregarded. There are frictions on the railway and of course in the air so that an amount of potentiel energy is lost during the motion so that the minimum height should be much higher. Nowadays a high initial velocity is also provided at the higher point so that is no more necessary to build very high structures.
when calculating gravitational potential (phi) of a rocket for example, do we take the radius as the distance from the centre of mass of the planet or do we use the radius as the distance between the rocket till the surface of earth?
Hi sir, how are u doing? Really thnx a lot for making this video sir, I'll sure be sharing this video with my friends, Once again thnx and really a awesome video
At the top of the loop, shouldn't you consider the reaction force from track pushing down as well as gravity? And if it is 'centrifugal force' as you say, how do you know that balances the reaction force?
