For the vertical system, the mass oscillates about the equilibrium position where kx=mg (so x=mg/k is how far the spring is stretched.), and there is elastic PE at the equilibrium position. Normally, we normally transform the problem to a new variable (distance from equilibrium) to verify SHM, or we might simple verify conservation of energy at some critical points, however, it would take too long to do the algebra in this forum.
Hi Mr. Doner, I may have found a mistake at the summary of this video. It is the sketch of the velocity graph, shouldn't it be the same as the one you showed at 13:12? Thank you. Great vids.
Hey!DONER velocity and time graph of an S.H.M at zero is zero so the graph must start from zero but at 18:53 the graph is starting from maximum and i guess the K.E and P.E energy graphs were interchanged in their positions in that slide AM I CORRECT OR THE THING WHICH I THOUGHT WAS WRONG?
The KE and PE graphs are consistent with the v-t. The oscillator can begin from any point. I believe there were some inconsistencies in the video and I replied to those comments earlier.
+Abbas S The acceleration and displacement graphs are in opposite directions since the force and acceleration is always opposite the displacement, however, the velocity graph is horizontally shifted compared to the displacement graph.
+Chris Doner (C. Doner's IB Physics) I understand that, however, I don't understand how the velocity graph in the video and in the summary are the same.
Mr. Doner, because of isochronous oscillations, a pendulum released at 30 degrees and the same pendulum released at 60 degrees should have the same time period yea? However, when I tried that in the PHET simulation, the time periods were differing. I am confused
i dont get why the period stays the same regardless of amplitude. amplitude is where the x value is greatest so shouldn't that mean there is a greater force required to move the pendulum? wouldn't that require a greater amount of time?
Larger amplitude means there will be more average force in the spring, so a greater average speed, but it also means that the object travels further. These two effects kind of cancel each other out.
Angular frequency shows up under circular motion in the SL course. You should know what it is. I cover it in the engineering option...rotational motion.
pls dont stop making these videos....you are life saver to us.
Thanks Mr. Doner, now I can buy a grandfather clock and know it will accurately give me the time
cramming 4 days before my exam... thank you so so much!!
Good luck!!
30:51
My daughter having her best day ever.
@@donerphysics :D
You're doing a Great job sir! Thank you so much for such good content! :D
Thank you，really useful for an IB student !!!
Glad it was helpful!
in 16:26 for the 3rd example, would be PE be higher when the mass is at a greater height than at the bottom because of GPE? and therefore not SHM?
For the vertical system, the mass oscillates about the equilibrium position where kx=mg (so x=mg/k is how far the spring is stretched.), and there is elastic PE at the equilibrium position. Normally, we normally transform the problem to a new variable (distance from equilibrium) to verify SHM, or we might simple verify conservation of energy at some critical points, however, it would take too long to do the algebra in this forum.
you are the best
This is extremely helpful!!! Thank you soooooo much!!!
Hi Mr. Doner, I may have found a mistake at the summary of this video. It is the sketch of the velocity graph, shouldn't it be the same as the one you showed at 13:12? Thank you. Great vids.
I added an annotation but the annotations do not show anymore.
Mr. Doner, your videos are seriously a life saver. Do u have any videos on the Option C part of the syllabus, Imaging ??
There are a few in the playlist for Option C.
Hey!DONER velocity and time graph of an S.H.M at zero is zero so the graph must start from zero but at 18:53 the graph is starting from maximum and i guess the K.E and P.E energy graphs were interchanged in their positions in that slide
AM I CORRECT OR THE THING WHICH I THOUGHT WAS WRONG?
The KE and PE graphs are consistent with the v-t. The oscillator can begin from any point. I believe there were some inconsistencies in the video and I replied to those comments earlier.
I get it now and truely you are my saviour
i think the v over t graph in the summary is wrong;.
Thanks for reminding me. One of my students told be about this but I forgot to add an annotation until now.
your welcome. Your videos are really helpful!
For the sake of strictness, I think you should say that the angle is always lesser or equal to 180 degrees instead of less than 180 degrees
Yes, thank you!
Mr. Doner in your summary shouldn't the velocity graphy be flipped over the x-axis opposed to what you have?
+Abbas S
The acceleration and displacement graphs are in opposite directions since the force and acceleration is always opposite the displacement, however, the velocity graph is horizontally shifted compared to the displacement graph.
+Chris Doner (C. Doner's IB Physics) I understand that, however, I don't understand how the velocity graph in the video and in the summary are the same.
+Abbas S
Aha! Right thank you. I will add an annotation. The v-t graph in the summary should begin with a positive not negative velocity.
@lololololol9349 An annotation was added long ago, but they do not show up on mobile devices.
I LOVE YOU
Mr. Doner, because of isochronous oscillations, a pendulum released at 30 degrees and the same pendulum released at 60 degrees should have the same time period yea? However, when I tried that in the PHET simulation, the time periods were differing. I am confused
Pendulums are only isochronous for small angles of release.
Furthermore, in the last IB question, shouldn't TOTAL energy be always constant?
Total energy is constant in a closed system, but here we are changing the system and making a comparison.
I love you
at 2:28 there's some sound :o
My daugther.
i dont get why the period stays the same regardless of amplitude. amplitude is where the x value is greatest so shouldn't that mean there is a greater force required to move the pendulum? wouldn't that require a greater amount of time?
Larger amplitude means there will be more average force in the spring, so a greater average speed, but it also means that the object travels further. These two effects kind of cancel each other out.
Hi Mr. Doner, I can't seem to find your videos on topic 4.2- Travelling waves. Do you have any?
P.S- Your videos are super helpful!
+shria gupta
There is a playlist with 2 videos. One is called oscillations, and the other is called wave characteristics.
Simple Harmonic Motion involving angular frequency is HL, right?
Angular frequency shows up under circular motion in the SL course. You should know what it is. I cover it in the engineering option...rotational motion.