According to the law of conservation of mass, which of these is true. a. when a physical change occurs, some of the mass is destroyed. b. when a chemical change occurs, some of the mass is destroyed. c. when both a physical and chemical change occurs, mass is added. d. when either a physical or chemical change occurs, no mass is destroyed. i also don't know which subject this would sorry

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.

Aball has an initial velocity of 3 m/s. if there is no friction, what is the highest it could roll?

Wavelength of 125 meters is moving at a speed of 10 m/s. what is it's frequency?