Two sound sources send identical waves of 20 cm wavelength out along the +x axis. At what minimum (non-zero) separation of the sources will a listener on the axis beyond them hear: (a) the loudest sound (b) the weakest sound?

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.