Answer: D. it has been demonstrated to be without exception under certain stated conditions.
Explanation:
A <u>Law</u> is an affirmation (something established) based on repeated long-term observation of a phenomenon that has been studied and verified.
That is: A law is present in all known theories and therefore is considered universal. In addition, a law can not be refuted, nor changed, because its precepts have been proven through various studies.
<u>Unlike theory</u>, which is the set of rules and principles that describe and explain a particular phenomenon and <u>is subject to changes as new evidence emerges that gives meaning to it. </u>
Then, based on what is explained above, the law of universal gravitation is a statement that exists because it was rigorously tested and verified, therefore it can not be refuted.
the greater the <u>mass</u> of an object the more force is needed to cause acceleration
Explanation:
Usually when we think of waves, we think of transverse waves. These are waves where points move up and down perpendicular to the motion of the wave. Examples include water waves, whipping a rope, or even doing the "wave" in a crowd. You can think of these as "two dimensional" waves.
Longitudinal waves are waves where points move left or right, parallel to the motion of the wave. In other words, there is compression and expansion of the medium. Examples include sound waves, or pulses in a slinky.
Because the top layer of a pool will be warmer than the bottom layer, that why filtration is important to cycle the water evenly.
