What do understand by the efficiency of a machine? By using a block and tackel a man can raise a load of 720 N by an effort of 180 N. Find the mechanical advantage of the method.

Imagine an alternate universe where the value of the planck constant is . in that universe, which of the following objects would require quantum mechanics to describe, that is, would show both particle and wave properties? which objects would act like everyday objects, and be adequately described by classical mechanics?