Two carts, moving at opposite directions, collide and recoil. Which question would help determine if the system of two carts is open or closed? A) Do the carts have the same mass? B) Do the carts have different initial velocities? ) Is energy transferred from one cart to the other? D) Is the total momentum constant before and after the collision?

In a system, when potential energy decreases, then entropy also decreases. true false

How are positive ions different from neutral atoms

The center of a long frictionless rod is pivoted at the origin, and the rod is forced to rotate in a vertical plane with constant angular velocity \omega. write down the lagrangian for a bead of mass m threaded on the rod, using r as your generalized coordinate, where r, \phi are the polar coordinates of the bead. (notice that \phi is not an independent variable since it is fixed by the rotation of the rod tobe \phi = \omega * t) solve lagrange's equation for r(t). what happens if the bead is initially at rest at the origin? if it is released from any point ro > 0, show that r(t) eventually grows exponentially. explain your results in terms of the centrifugal force m* \omega ^2 *r.