Identical cellos are being tested. one is producing a fundamental frequency of 130.9hz on a string that is 1.25m long and has a mass of 109g. on the second cello the same string is fingered to reduce the length that can vibrate. if the beat frequency produced by these two strings is 4.33hz, what is the vibrating length of the second string?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

Scientist have use computer models to create a series of maps that show how susceptible coastal cities in island countries are to the sea rising at different levels.the map shows that a 1 meter rise would swap cities all along the us eastern seaboard. a 6-meter sea level rise with sub merge a large part of florida. thermal expansion has already raise the oceans 10 to 20 centimeters the most likely cause,directly and indirectly, for such a rise in sea level is