I couldn't quite follow you past 7:29 (angular momentum of non-rotating object??) , but this can not be true: V(tip) = 3/2 V(initial) - Because if that was true that would mean that when the rod hits the table, the acceleration of the tip would have to be infinite. Tip is moving at V (initial). The moment that the rod hits the table, all of a sudden the tip is moving 3/2 times faster. Finite change of velocity over infinitely small time = infinite acceleration - I liked the left part :) Other than saying that the force Mg is acting in the middle of the rod. It's not. Gravity is acting at every mass particle that is a part of the rod. It's just that the center of mass is a useful concept. For example, we can see right away that although it's counterintuitive, nothing unholy happens in Veritasium's ladder fall. Because the center of the mass for the left ladder is actually falling slower than completely free fall ladder on the right side. But you're right - dynamics of a _perfectly rigid body_ can be _viewed_ as if the entire mass was concentrated at CM and all external forces were acting there.
U got the perfect explanation to veritasium's video. Nice and precise physics, ez to understand.
This is one of the very few videos very I understand the hard physics and math behind it.
Glad you think so!
Great explanation for everyone
nice presentation and explanation, keep up the good work
Thanks, will do!
Very informative thanks
I couldn't quite follow you past 7:29 (angular momentum of non-rotating object??) , but this can not be true:
V(tip) = 3/2 V(initial)
- Because if that was true that would mean that when the rod hits the table, the acceleration of the tip would have to be infinite.
Tip is moving at V (initial). The moment that the rod hits the table, all of a sudden the tip is moving 3/2 times faster.
Finite change of velocity over infinitely small time = infinite acceleration
- I liked the left part :)
Other than saying that the force Mg is acting in the middle of the rod. It's not. Gravity is acting at every mass particle that is a part of the rod.
It's just that the center of mass is a useful concept. For example, we can see right away that although it's counterintuitive, nothing unholy happens in Veritasium's ladder fall. Because the center of the mass for the left ladder is actually falling slower than completely free fall ladder on the right side.
But you're right - dynamics of a _perfectly rigid body_ can be _viewed_ as if the entire mass was concentrated at CM and all external forces were acting there.
Why it is 1/3 in (1/3)*M*L^2
instead of 1/2 or 1 or anything else ?