1. To move a box up an inclined plane a woman expends 200 J of work, but the amount of work produced is 70 J. What is the efficiency of the work performed?

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The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings. 

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.