Woah Billy, Bob, and Bo have changed quite a bit. Just wanted to add on thanks for the AP1 review I felt pretty good on the exam because of those videos
Great video! One suggestion I had was maybe to give some intuition on why certain things do or do not affect the period of simple harmonic motion instead of just showing us the equations. Thanks for the video! Keep up the great work!
"Everybody brought mass to the party" is the first takeaway concept for why period is independent of the mass. Both the restoring force and inertial property are proportional to mass and come as a package deal.
I was wondering, would you be doing a review of the AP Physics 1 FRQ for 2018? I think it would be a really good idea as the topics covered by that test were pretty niche. (Gravitational Period, Resistivity of cylindrical electric dough, Rotation, strings, and springs) The last two aren't that niche though.
Flipping Physics oof could you please try to find time to do them? i understand you can’t just do everything people ask as soon as they want it because you have your own life haha but it would be so helpful to so many of us and i would be so grateful if you could work it into your plans! you make this stuff really straightforward and easy to understand where teachers and other youtubers haven’t. again, i understand if you can’t and i hope this didn’t come off as entitled. thank you so much for everything you do for us!
The equation of motion of a pendulum takes the form of: theta"(t) + g/L*sin(theta(t)) = 0 Where the " indicates second derivative, and theta(t) means angle theta is a function of t. In order for the equation to give the same form of the solution of simple harmonic motion as we get for the mass-spring example, we need to make a small angle approximation that sin(theta) = theta. This allows for solving it in closed form, such that theta(t) = A*cos(omega*t + phi), where A and phi depend on initial conditions. We cannot solve this differential equation in closed form with the pesky sin(theta(t)) term. You end up needing to use infinite series of the sine function, to account for large amplitudes and advanced techniques of solving differential equations. Hyperphysics has a large amplitude pendulum calculator that does exactly that, and shows you that an angle of 22 degrees or less, will yield a 1% error or less in period. This allows you to quantify "small" in "small amplitude pendulum".
I'm taking the Exam tomorrow, just reviewing a bit of Simple Harmonic Motion before going to sleep. Good luck to everyone taking the exam tomorrow too!
Love you sir ....and very very thank you sir...I am see your channel before 2days...I am surprise.. That wow what's amazing approach to explain concept and animation.... Very very thank you sir...
Absolutely wonderful demonstrations, thank you so much for the visuals!! It truly is a shame, however, that you could not go to the moon for the last demonstration :(
@@FlippingPhysics I've tested it during an airplane holding pattern. A 25 cm pendulum ordinarily swings in 1 second periods. In 20 seconds, it completes 21 swings instead of 20.
Way late in answering, but here you go: If we start from t=0 s and have no phase shift, one full period has passed when everything "inside" the trig function equals 2π
They graduated!! Nope, just kidding. They will be back after the next video. I had an opportunity to have some "substitute students" for a few videos and it seemed like a good idea.
Sidney Boakye basically I just like explained that the amplitude doesn't really change based upon the amount of object you put on top of the block. I couldn't remember but I think I put down that the amplitude isn't really based upon the period of the shm system. I may be wrong for writing that portion though
Fun fact: if the pendulum is accelerating upward, it behaves as if gravity is higher and when it is accelerating downward, it behaves as if gravity is lower. Just because the acceleration of the top of the pendulum isn't in the period equation, doesn't mean it doesn't affect the period. This is because the equation doesn't work at all when there is a constant acceleration applied to the top of the pendulum that isn't also applied to the bottom or vise versa except for what ever acceleration vector is holding up the top of the pendulum (which happens to be equal to gravity). In fact, if you assume the string isn't there and replace gravity with the difference between the net acceleration of both parts of the pendulum, the equation would work perfectly fine. For instance, if a pendulum is on an elevator that is accelerating upward, then you need to take the net acceleration of the top part (which is equal to the elevator's acceleration), and the net acceleration of the bottom part (which would be equal to gravity), find the difference and use that for gravity. Since they are moving in opposite directions, they would add together giving you gravity+elevator acceleration. Plug this in to any pendulum equation with gravity in it and you will get the correct answer. I had a worksheet in my AP Physics class with a problem about the period of a pendulum on an accelerating elevator, and I got it wrong because the teacher insists that the acceleration of the top of the pendulum doesn't affect the period :|
The g term here is the apparent acceleration of gravity if the reference frame is being interpreted as inertial. So this does mean that you combine accelerations when accelerating upward and subtract when accelerating downward. Not really sure what you are implying about the top of the pendulum, as the whole system is accelerating upward/downward at the same rate (ignoring upward/downward component of the pendulum bob).
Woah Billy, Bob, and Bo have changed quite a bit. Just wanted to add on thanks for the AP1 review I felt pretty good on the exam because of those videos
Don’t worry, Billy, Bobby, and Bo will be back soon enough. Glad to know I helped you study. I hope it went well.
Great video! One suggestion I had was maybe to give some intuition on why certain things do or do not affect the period of simple harmonic motion instead of just showing us the equations. Thanks for the video! Keep up the great work!
"Everybody brought mass to the party" is the first takeaway concept for why period is independent of the mass. Both the restoring force and inertial property are proportional to mass and come as a package deal.
GOOD LUCK ON THE EXAM TOMORROW
AGREEEEEED. Good luck y'all!
7:20 Apology accepted. I can manage without going to space , yeah it will be tough but I'll do it any way.
I was wondering, would you be doing a review of the AP Physics 1 FRQ for 2018? I think it would be a really good idea as the topics covered by that test were pretty niche. (Gravitational Period, Resistivity of cylindrical electric dough, Rotation, strings, and springs)
The last two aren't that niche though.
Not in my current plans. Dan Fullerton of APlusPhysics usually does. ruclips.net/user/FizziksGuy
Flipping Physics oof could you please try to find time to do them? i understand you can’t just do everything people ask as soon as they want it because you have your own life haha but it would be so helpful to so many of us and i would be so grateful if you could work it into your plans! you make this stuff really straightforward and easy to understand where teachers and other youtubers haven’t. again, i understand if you can’t and i hope this didn’t come off as entitled. thank you so much for everything you do for us!
a short video answered all my questions
That’s how I roll.
Could you plz quicly explain why its no longer a simple harmonic motion when the angle is greater than 15.Thank you
Sure. See: www.flippingphysics.com/shm-pendulum.html
The equation of motion of a pendulum takes the form of:
theta"(t) + g/L*sin(theta(t)) = 0
Where the " indicates second derivative, and theta(t) means angle theta is a function of t.
In order for the equation to give the same form of the solution of simple harmonic motion as we get for the mass-spring example, we need to make a small angle approximation that sin(theta) = theta. This allows for solving it in closed form, such that theta(t) = A*cos(omega*t + phi), where A and phi depend on initial conditions.
We cannot solve this differential equation in closed form with the pesky sin(theta(t)) term. You end up needing to use infinite series of the sine function, to account for large amplitudes and advanced techniques of solving differential equations. Hyperphysics has a large amplitude pendulum calculator that does exactly that, and shows you that an angle of 22 degrees or less, will yield a 1% error or less in period. This allows you to quantify "small" in "small amplitude pendulum".
4:20 Get itttt 🔥🔥🔥🔥🔥🔥🔥🔥
I'm taking the Exam tomorrow, just reviewing a bit of Simple Harmonic Motion before going to sleep. Good luck to everyone taking the exam tomorrow too!
And best of luck to you as well!
Thanks a lot for your efforts creating these amazing videos. Your website is the only one white listed in my Ad blocker.
Thank you for that!!!
Flipping Physics I think I should be the grateful one here, you are a gem among teachers, Keep doing what you do
Very nice addition of the 45 degree non-SHM pendulum to emphasize the point.
Thanks. I thought it would be useful to actually show an example that it is _not_ simple harmonic motion.
best explanation man keep it up, just subscribed
Love you sir ....and very very thank you sir...I am see your channel before 2days...I am surprise.. That wow what's amazing approach to explain concept and animation.... Very very thank you sir...
You are very welcome!
When she said who was bob I just dropped dead because that is so funny XDD
Maybe Bobby can join the pendulum bob, as a demonstration that swing period is independent of mass.
Absolutely wonderful demonstrations, thank you so much for the visuals!!
It truly is a shame, however, that you could not go to the moon for the last demonstration :(
someday?
@@FlippingPhysics I've tested it during an airplane holding pattern. A 25 cm pendulum ordinarily swings in 1 second periods. In 20 seconds, it completes 21 swings instead of 20.
I have a question: how do you find the period of a system given a position equation
Way late in answering, but here you go: If we start from t=0 s and have no phase shift, one full period has passed when everything "inside" the trig function equals 2π
Like the new students... Very smart! What has happened to Billy, Bobby and Bo?! 😀
They graduated!!
Nope, just kidding. They will be back after the next video. I had an opportunity to have some "substitute students" for a few videos and it seemed like a good idea.
Flipping Physics love it! It's an excellent run through of SHM!
Did Bo get glasses
Oh thx gosh, at least I answered that last FRQ abt the amplitude correctly
I hope so!!!
How so? @NeonArtz
Sidney Boakye basically I just like explained that the amplitude doesn't really change based upon the amount of object you put on top of the block. I couldn't remember but I think I put down that the amplitude isn't really based upon the period of the shm system. I may be wrong for writing that portion though
NeonArtz - Hakim C. Ooof, I couldn't pick between that and the one which said it increases. Eventually I went with the larger mass, mb. 😐😅
lol thats what i did for the practice AP.
Although im glad i used my extended time to truly think over each of the questions
great video, really like the new explaination, although it also looks like a repetetive loop of a vertical spring (:
And that is a problem because....?
it isnt
Fun fact: if the pendulum is accelerating upward, it behaves as if gravity is higher and when it is accelerating downward, it behaves as if gravity is lower.
Just because the acceleration of the top of the pendulum isn't in the period equation, doesn't mean it doesn't affect the period. This is because the equation doesn't work at all when there is a constant acceleration applied to the top of the pendulum that isn't also applied to the bottom or vise versa except for what ever acceleration vector is holding up the top of the pendulum (which happens to be equal to gravity). In fact, if you assume the string isn't there and replace gravity with the difference between the net acceleration of both parts of the pendulum, the equation would work perfectly fine. For instance, if a pendulum is on an elevator that is accelerating upward, then you need to take the net acceleration of the top part (which is equal to the elevator's acceleration), and the net acceleration of the bottom part (which would be equal to gravity), find the difference and use that for gravity. Since they are moving in opposite directions, they would add together giving you gravity+elevator acceleration. Plug this in to any pendulum equation with gravity in it and you will get the correct answer.
I had a worksheet in my AP Physics class with a problem about the period of a pendulum on an accelerating elevator, and I got it wrong because the teacher insists that the acceleration of the top of the pendulum doesn't affect the period :|
The g term here is the apparent acceleration of gravity if the reference frame is being interpreted as inertial. So this does mean that you combine accelerations when accelerating upward and subtract when accelerating downward. Not really sure what you are implying about the top of the pendulum, as the whole system is accelerating upward/downward at the same rate (ignoring upward/downward component of the pendulum bob).
"apparent acceleration of gravity" is probably a better way of putting it.
I have survived the exam!!!!! Anyone else feeling confident?!?!
I hope you all are!
"No. I would remember Bob."
You mean BobBY.
edit: This is just for laughs, no offence intended.
"Fortnights"
"FoRTnITEs"
a fortnight is 14 days. it came from old English when people said fourteen nights, or fort-nights
fortnite
My uncle got in my roodjfnkenckbd
Ayo shawty kinda bad