At the security area, people walk through a large coil of wire and through a weak AC magnetic field. What is the result of a small piece of metal on a person that slightly alters the magnetic field in the coil?A. Temperature differences are induced in the metal that can be detected by the coil of wire, this in turn changes the AC current in the coils and sets off an alarm. B. Radiation is induced in the metal that can be detected by the coil of wire, this in turn changes the AC current in the coils and sets off an alarm. C. Electric currents are induced in the metal that changes the magnetic field, this in turn changes the AC current in the coils and sets off an alarm.

To place a communications satellite into a geosynchronous orbit at an altitude of 22,240 mi above the surface of the earth, the satellite first is released from a space shuttle , which is in a circular orbit at an altitude of 185 mi, and then is propelled by an upper-stage booster to its final altitude. as the satellite passes through a, the booster's motor is fired to insert the satellite into an elliptic transfer orbit. the booster is again fired at b to insert the satellite into a geosynchronous orbit. knowing that the second firing increases the speed of the satellite by 4810ft/s, determine (a.) the speed of the satellite as it approaches b on the elliptic transfer orbit, (b.) the increase in speed resulting from the first firing at a.