You have already managed to be one of the internal voices of mine which i can bring out and talk to when i need it ! Thanks for all the content that you have uploaded so far .. :)
Thank you for your videos that make physics easier to understand. I am currently struggling with physics and I have an exam Tuesday and these videos are helpful.
Can not even believe how much this video has made my mind clear....I am a senior of Civil Engineering department and we use moment of inertia in our calculation a lot, and I do no how to calculate it and use it in various equations and formulas, but I never knew the true definition and meaning of it until just now....this is just so shocking
I have never thought of why my bicycle tire is designed the way it is, versus it being a solid disk. It makes so much sense now! It's moment of inertia is greater because the mass is distributed further away from the axis of rotation. Therefore, once you get it going, it is harder to stop comparatively (assuming mass is the same). Thank you so much!
I love your videos. You helped me ace my cal-based physics test over the waves/harmonic motion/fluid dynamics. Wonderful explanations, you're like the PatrickJMT of physics. Judging from the amount of videos you have, I'll be using your channel for a long time.
Wow. You are totally correct in catching my error. In fact, that's not even fixable, because it gives the wrong answer. I'm going to delete the end of this video and make a supplement. THANK YOU!!
For those who missed the disc and are still curious about how to proceed: Consider a small ring-shaped element of a very small thickness dx at an arbitrary distance x from the centre and find its mass in terms of the mass of the entire disc (M). that can be done by finding the disc's mass per unit area (assuming it to be homogeneous), and then multiplying it with the area of the ring shaped element (total length×thickness). Now find the moment of inertia of the ring you've just made, which is its mass multiplied by its distance from the centre (x). Lastly integrate this expression (I'm assuming you know a bit of calculus) within the limits 0 and R (the radius of the disc) to get the moment of inertia of the entire disc. You should get the result I= (1/2)MR^2
sorry I made a slight error there. while finding the moment of inertia of the ring-element you've got to multiply it's mass by the square of its distance from the centre (x^2), not merely x
Thank you thank you thank you thank you! When I asked my teacher about the calculation of the rotational inertia she said: "it's everything tabled". ( wow that was soooo helpful! ARRRRRGHHHH HULK SMASH!)
Cuz the moment of inertia of ice skater decreases as he/she pulls in his/her arms. By the law of conservation of angular momentum, her angular speed increases. Thus, spin faster. Learning Objective achieved !! ありがとう !
Hi doc, working my way through all your videos. This video seems to end before you finished your derivation of the disk's rotational inertia. Was that on purpose, or an upload malfunction?
+Doc Schuster Using calculus is the only way because the moment of inertia varies with r. There's nothing wrong with demonstrating how to use calculus in the tutorial - it'll help people with their integrating skills. Thanks for your video - it taught me the subject so much more clearly than my lecture notes!
+sixcupsoftea I keep hoping that we can in some way wave our hands and talk about weighted averages. Yeah, I'll just have to go full blown, maybe. I'm glad it helped, though.
AHH! Doc sir, i need you to explain the calculus, my teacher was a noodle and couldn't explain it, likely as he didn't know himself. Do you explain it anywhere?
Hey Doc, What about the moon ? According to todays astronomers, it is not like your apple on pen in that the moon rotates about an internal axis AS WELL AS the pivot (barycenter) Tesla said this was untrue - articles.adsabs.harvard.edu//full/1993POBeo..44..119T/0000122.000.html However he's fairly alone. Is there a flaw in his math ?
