If you see that a hot-air balloon is rising above the top of a hill, the top of the hill is called the reference point. Correct answer: D The reference point is a point (object, place) used for comparison to determine if something is in motion, assuming that the reference point is stationary, or not moving.
Well, there is a kind of magnet to pick up a coin.. I think you can pick up a needle with one too.. I think safety pins. depending on what its made of though.
