What does sound travel the fastest throught wood, water, vacuum or air

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.

What is the relationship between wavelength of light and the quantity of energy per photon?

Consider the phase change taking place in the picture. you could use all but one statement to describe what is happening here. that is: a) temperature is increasing. b) kinetic energy is increasing. c) the space between the particles remains the same. d) the attractive force between the particles is decreasing.