Hello Mr. Doner. I have graduated IB this year, and I would just like to say that, without your videos, I would have definitely not passed HL Physics. I am hopeful that you continue helping students out there, your videos are beneficial to all of us, and I really appreciate your efforts in making free videos to IB students out there. Thank you so much. Regards, Ahmad.
Hi, Chris. When marking the normal force, you draw the arrow from the centre of mass of the object(6:48). I think it should be drawn from the point of contact between the object and the surface.
Centre of mass is standard since forces act on the center of mass, however, you will see lots of variations and these primarily depend on convenience and what is being emphasized. For instance, if two forces act in the same direction, we can not see them if we draw them on top of each other, or suppose you have two separated objects like the Earth and moon.
Hello sir, I would like to ask you if it's possible to start adding the HL IB physics material. Your videos are unbelievably helpful. I hope you manage finishing those 4 chapters as soon as possible. Since the school year is starting soon, I am really counting on you!
Hey, I had a question @20:55 / 21:09: do I draw the tension force from the center of the mass or the top part where the rope and mass are directly in contact?
Just try to communicate well. You need to show somehow what object the force acts on and its direction, and hopefully its relative size. The central dot is to represent the center of mass of the object which is what he force acts on, but this is not especially important information.
Hello Mr Doner, Just wondering if you could do any more circular motion videos? Thank you for all the videos! Been helping me alot in physics, funnily enough before watching your videos, I got 33% on the mechanics test, I then revised through your videos and got 65% which puts me at a 5. Thank you.
I have redone the UCM video and will post shortly. Was there something you were looking for specifically on circular motion? There are already posted videos on UCM and gravity, and applications of UCM.
in the first exercise (The ball and the pin) should not we draw a normal force for the pin after collision that is perpendicular for the the object itself ? and I did not get the force of the Contacr C, is it like a tension that is opposite to the direction of the ball but is with the direction of the pin and vice versa? I mean or can we just label it as a force of contact in IB exams ?
There is no normal force after contact because it is not in contact with anything. It is in the air. A contact force is just what it sounds like...it is a force due to contact with another passive object. It is called a normal force because it is always perpendicular (normal to) the surface of contact.
In the last diagram with the two blocks hanging on one string, why are the tensions similar? Wouldn't the part of the string holding up the heavier block have more tension than the part of the string holding up the smaller block?
That would be true if the pulley had mass. Imagine the pulley is frictionless so that it does not move at all, perhaps that will enable you to see why the tension must be the same throughout the rope.
Great videos Mr. Doner! I had one question. A lot of your playlists show that "unavailable videos are hidden". I wanted to know if you have intentionally hidden those videos or is because of a glitch. I have purchased the new video membership so I do not think that there is any problem because of that. I ask this question because I want to make sure that I am covering all the syllabus by watching your playlists and not miss out any part because of the hidden videos. For example, in the Forces 2.2 Playlist, the new translational equilibrium video is missing and the playlist does show that there in 1 unavailable video that is hidden. It would be great if you could answer this question of mine.
Thank you so much! However, the playlist still shows that 1 unavailable video is hidden. In addition, there is no video on the intensity and amplitudes in the playlists pertaining to Waves SL. The playlist for waves characteristics does show that 1 unavailable video is hidden so it might be that the video pertaining to the intensity and its relation with the distance and amplitude is hidden.
I discuss intensity and amplitude in other topics such as topics 8 and 9. It is somewhat misplaced in topic 4 as there are no real applications other than to know what intensity and amplitude are. Some videos are hidden just because there is a better video available and I didn't delete the old video.
@@maisan6234 if there were no gravity the tension and speed would be constant. As the gravitational potential energy (height) increases the ball slows down, and this means the net force needed for circular motion will change. Since the weight does not change, the tension does all the adjusting.
@@colchi2547 That seems to be the Atwood Machine. If a foot kicks a ball, the ball exerts an equal and opposite force on the foot. This causes the foot to slow down.
