Isaac Newton published his work on gravity in the Philosophiæ Naturalis Principia Mathematica (Latin for Mathematical Principles of Natural Philosophy) in July 1687. In 2-3 complete sentences, detail observations you can make today that would lead you to the same conclusions Newton came to about gravity.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.