27.4: Proposals to mine resources from the Moon have included suggestions that the goods could be launched toward Earth using an electromagnetic railgun, also called a mass driver, which is essentially an apparatus like that described in the preceding problem, with a cargo capsule incorporated into the conducting bar. With rails spaced 1.00 m apart and a magnetic field of 0.877 T, what emf would be needed to achieve a speed that’s 50% greater than lunar escape speed? Wolfson, Richard. Essential University Physics, Volume 2 (p. 541). Pearson Education. Kindle Edition.

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.