What is the function of the commutator in an
electric motor?
a. it decreases the current in the coil.
b. it reverses the current in the coil.
c. it reverses the poles of the permanent
magnet.
d. it weakens the field of the permanent
magnet.

Which are advantages of renewable resources? check all that apply. renewable energy supplies are completely reliable everywhere. some renewable resources will never be used up. little or no waste is produced by renewable resource plants. electricity can be generated in large quantities. many renewable energy facilities have lower operating costs.

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

Which of the following forces require physical contact? tension air resistance friction magnetic force applied force