Well Inertia means something wants to stay in place, and in reality that coin wants to stay in one place, If you placed it on an index card on a cup, and SLOWLY pulled it, it wouldn't be fast enough to overcome that force, if you pulled it quickly that coin would stay in place and drop into the cup.
Efficiency is calculated through dividing the actual mechanical advantage by the hypothetical mechanical advantage:
- the actual mechanical advantage is 9J because that's how much work the light bulb doing
- the hypo. mechanical advantage is 100J. Ideally, in a perfect world, the light bulb can convert 100J input into 100J output, but do to resistance and other factors it is not possible.

change the decimal to a percentage:

the light bulb had 9% efficiency
The answer is; Irregular.
It could be A :) not sure tho
The ampere (A) is a basic SI unit consisting of the amount of electric charge or number of electrons that pass a point in a electrical circuit in one second. The volt (V) is the electrical potential causing electrons to move through a wire. It is a joule of energy per coulomb of charge.