When an electric current flows through a long conductor, each free electron moves
a. back and forth between the ends of the conductor.
b. from one end of the conductor to the other end.
end of exam
c. with a speed of 300,000,000 m/s.
d. through a relatively short distance.

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.