Recent content by mattlfang

btw, I just realized, if we choose the conservation of AM wrt the end of the rod where the bullet hits, it's even simply since the angular momentum wrt to that end is 0.

here is the diagram I drew. I assume wheel A has mass = 1, wheel B has mass = 3, velocity of A is (1,0), and velocity of B is (0,2). Then the velocity of the center of the mass of the system is (0.25, 1.25) vector OD. The velocity relative to the center of the mass of the system is vector AG...

yes, exactly, but it doesn't look easy to express it.

they are rotating in opposite directions yes, but I did mention the velocities are at right angles, let me make that more clear.

two moving and rotating, uniformly weighted disks perfectly inelastic collide. The disks are rotating in opposite directions (see the diagram) At the moment of their collision, the angles between their velocity and the line connecting their centers are 45 degrees. The velocities are therefore in...

yes just fixed... sorry

indeed, my second one was wrong. yes ineed, I don't have to have 4 equations for four unknowns. Now I have figured out my problem. Thanks for the help. ##mv = MV## ##\frac{mvL}{2} = I \omega = \frac{M}{12} L^2 \omega = \frac{M L^2 \omega}{12}## ##\frac{mv^2}{2} = \frac{MV^2}{2} + \frac{I...

oh indeed... so I should have ##mv = MV## ##mvL = I \omega## ##\frac{1}{2} m v^2 = \frac{1}{2} MV^2 + \frac{1}{2}I \omega^2## ##\omega \frac{L}{2} = V## here the angular momentum is w.r.t to the other end of the rod...

But now we have 2 equations but four unknowns...

That's true, but what exactly are wrong with my equations in the OP?

I got ##v = \omega## and ##m = I##, but nothing about ##L## can help me solve for ##M##?

yes, one end of the stick., I just made it more clear

A bullet with mass m, velocity v perfectly elastically, vertically collide with one end of a rod on a slippery plane and the bullet stops moving after the collision. Find the mass of the stick M the bullet stops moving after an elastic collision, so all energy is transformed to the rod. There...

Ok, I believe I get what you are trying to convey with your example. But I am not sure if exactly addresses my concerns. You are basically suggesting a model *similar* to below. A pendulum attached to a block that's freely sliding without friction on a rail. I agree in this case, conservation...

sorry, I don't quite understand this "the wheel riding on two rails with a gap between them that allows the stick to fall through and swing around" part? I don't fully understand what this system looks like? I start to suspect when people say "Rolling Without Slipping", it implies that...