Answer:
Removing some of the books reduced the mass of the box, and less force was needed to push it across the floor.
Newton’s first law because the airplane needs space to fully stop due to its inertia
The answer would be D, electromagnetic waves
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.
