Pseudo forces are real forces??? Hey guys, I really need an insight into what exactly are pseudo forces??? When I saw the derivation, it was more of a mathematical calculation, to find the acceleration of a particle with respect to a non inertial frame of reference. But doesn't the second law of motion strictly apply to inertial frames only, so why to extend it to non inertial frames just because the expression looks like the one in the second law??? Is it meaningful to talk about forces, with the non inertial frame of reference???? And if it is not even some force, and say we are applying the law of conservation of energy wrt some non-inertial frame, do we have to include it as an external force????