The scalar product between two 3-vectors can be written ab= ab cos ab, where a and b are the magnitudes of the vectors and eab is the angle between them. show that an analogous formula holds for two timelike 4-vectors a, b: a b= -ab cosh (abs (2) where a = (-a. a)1/, b = (-6. b)/2 and vab = tanh oab, for vab being the lorentz boost between the frame in which an observer whose worldline points along a is at rest and the frame for which an observer whose worldline points along b is at rest.

Answer choices? if there is any

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.

Special care would be an answer