Suppose there are two lakes located on a stream. clean water flows into the first lake, then the water from the first lake flows into the second lake, and then water from the second lake flows further downstream. the in and out flow from each lake is 500 liters per hour. the first lake contains 100 thousand liters of water and the second lake contains 200 thousand liters of water. a truck with 500 kg of toxic substance crashes into the first lake. assume that the water is being continually mixed perfectly by the stream. a) find the concentration of toxic substance as a function of time in both lakes. b) when will the concentration in the first lake be below 0.001 kg per liter? c) when will the concentration in the second lake be maximal?

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

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance