Horsepower = (RPM X Torque)/5454. Therefore if your horsepower is constant, input RPM raised by the gearbox decreases torque at the output. The opposite is true if the transmission reduces RPM.
Inertia and momentum are functions of mass, and the energy required to move / increase / decrease / stop the velocity of that mass.
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How can you be two places at once when you're actually nowhere at all?