A boy runs in a straight line and jumps onto the edge of a merry-go-round on a playground, which is initially not spinning. The boy initially runs tangent to the edge of the merry-go-round and jumps with the same velocity, as shown. After the jump he sits down and spins with the merry-go-round. Take the center of the merry-go-round as the origin of the coordinate system and ignore any frictional effects. Which of the following statements is true for the boy plus merry-go-round system ? Select exactly one answer.

1.The total initial angular momentum is zero and total momentum is not conserved.

2.The total initial angular momentum is non-zero and total angular momentum is conserved.

3.The total initial momentum is non-zero and total momentum is conserved.

4.The total initial angular momentum is zero and total momentum is conserved.

5.The total initial momentum is zero and total momentum is conserved.

6.The total initial momentum is zero and mechanical energy is conserved

A1200 kg car traveling north at 10 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. what is the total momentum before and after the collision?

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.

A2.0 μf capacitor and a 4.0 μf capacitor are connected in series across a 0.827-kv potential. the charged capacitors are then disconnected from the source and connected to each other with terminals of like sign together. find the voltage across each capacitor.