A18.6 m long steel beam is accidentally dropped by a construction crane from a height of 8.78 m. the horizontal component of the earth’s magnetic field over the region is 12.7 µt. the acceleration of gravity is 9.8 m/s 2 . what is the induced emf in the beam just before impact with the earth, assuming its long dimension remains in a horizontal plane, oriented perpendicularly to the horizontal component of the earth’s magnetic field? answer in units of mv