The two pucks of equal mass did not move linearly (they came to a stop) after the collision due to the conservation of linear momentum. however, since the two pucks, mutual center of mass does not coincide with either of the pucks velocity vectors, they have angular momentum. this becomes evident after the collision when due to conservation of angular momentum the two pucks spin around their mutual center of mass.
suppose we replace both hover pucks with pucks that are the same size as the originals but twice as massive. otherwise, we keep the experiment the same. compared to the pucks above, this pair of pucks will rotate:

a. at the same rate.
b. one-fourth as fast.
c. four times as fast.
d. twice as fast.
e. one-half as fast.

Answer quickly (15 points) a comet is approaching earth. describe earth’s gravitational pull as the comet gets closer to it. a. remain constant b. increase c. decrease d. reversed

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.

Astudent pushes a 60-n block across the floor for a distance of 10 m. how much work was done to move the block