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Fig. 21 shows a diver 50m below the surface of the water.
(a) The density of water is 1000 kg/m and the acceleration of free fall is 10 m/s
Calculate the pressure that the water exerts on the diver.

(b) The window in the diver's helmet is 150 mm wide and 70mm from top to bottom.
Calculate the force that the water exerts on this window.

What is the magnitude of the resultant vector round your answer to the nearest tenth

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.

What object a collides with object b and bounces back its final momentum is?