Astronomers believe that the deposit of lava in the giant mare basins did not happen in one flow but in many different eruptions spanning some time. indeed, in any one mare, we find a variety of rock ages, typically spanning about 100 million years. the individual lava flows as seen in hadley rille by the apollo 15 astronauts were about 4 m thick. estimate the average time interval between the beginnings of successive lava flows if the total depth of the lava in the mare is 2 km.

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?

Why should seat belts not be mandatory quick plz

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.