Propagation in seawater. transmission of electromagnetic energy through the ocean is practically impossible at high frequencies because of the high attenuation rates encountered. for seawater, take a = 4 s-m-1, epsilon r = 81. and mu r = 1. respectively. show that seawater is a good conductor for frequencies much less than -890 mhz. for frequencies less than 100 mhz. calculate, as a function of frequency (in hz), the approximate distance over which the amplitude of the electric field is reduced by a factor of 10.

1.in one challenge on the titan games, competitors have to lift 200 pounds up a long ramp. angel is able to move the weight in 42 seconds. anthony gets it done in only 38 seconds. which statement is true? angel has more power than anthony. angel does more work than anthony. anthony does more work than angel. anthony has more power than angel. 2.a mountain climber exerts 41,000 j of work to climb a cliff. how much power does the climber need if she wants to finish in only 500 seconds? power = work / time 20,500,000 watts 82 watts 0.0122 watts 41,500 watts 3.your family is moving to a new apartment. while lifting a box 83 joules of work is done to put the box on a truck, you exert an upward force of 75 n for 3 s. how much power is required to do this? (hint: you only need two of the 3 numbers given! ) power = work / time 249 watts 25 watts 2075 watts 27.7 watts

Most short-period comets do not have randomly oriented orbits because

A1500 w electric heater is plugged into the outlet of a 120 v circuit that has a 20 a circuit breaker. you plug an electric hair dryer into the same outlet. the hair dryer has power settings of 600 w, 900 w , 1200 w, and 1500 w. you start with the hair dryer on the 600 w setting and increase the power setting until the circuit breaker trips. under what setting does the circuit breaker trip.