12. A conducting 41.0 cm long rod makes contact with two metal rails which are fixed. There is a uniform magnetic field of 14.0 T that is directed out of the page as shown in the figure. What is the magnitude of the induced emf and the
direction of the induced current when the rod is moving at a speed of 3.15 m/s?

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is as it changes into other forms of energy.