A 50 kg car collided with a tree on the road at a speed of 50 m/s and fell into a ditch 3 seconds after reversing at a speed of 10 m/s. If the depth of the hole is 10 times the ratio of the last minute velocity to the initial speed of the vehicle , then if a 0.1 kg ball is thrown down from this height at a speed of 10 m/s, a 0.5 kg mass rat for the momentary velocity before touching the ground .What speed will be gain tha rat?

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.