Why does the surface of the sun appear to have a sharp edge?

Which of the statements about waves is true? a. in longitudinal waves, particles move perpendicular to the direction the wave is traveling. b. both transverse and longitudinal waves can travel through water c. electromagnetic waves are a type of longitudinal waves. d. in a transverse wave, particles move parallel to the direction the wave is traveling.

Assuming weightless pulleys and 100% efficiency, what is the minimum input force required to lift a 120 n weight using a single fixed pulley?

Edward tolman explained the results of his study by theorizing that the rats were learning about the maze during every trial but they a. were agitated because other groups were getting reinforcement b. could not remember how to demonstrate it without reinforcement c. were not motivated to demonstrate it without reinforcement d. seemed to be too lazy to actually work without reinforcement