4. The kinetic energy (KE) and gravitational potential energy (PE) for an object are shown Energy (J) as functions of time in the graph on the right. What is the change in total mechanical
energy of the object for the 5 seconds shown?
(A) 0 J
(B) 2.5 J
(C) 5 J
(D) 15 J

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.