A pacemaker uses an RC circuit for timing. (a) If the pacemaker is to operate at 72 beats/min,
and if the circuit “fires” when the capacitor is 65%
charged, what must the time constant be?
(b) When C 5 7.50 mF, what value of resistance should
be used?

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

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.

If a balloon is taken outside on a very cold day, what will occur?