is the increase in density of a medium due to wave travel.

Explanation:

Such type of the longitudinal waves that causes compression during the travelling through the medium is called as compression. Generally, displacement of the medium takes place in this wave travelling conditions. There are many waves that are considered as longitudinal waves such as sound waves, seismic p-waves and some other. Waves have different types of properties that are changed due to different medium.

none, its a machine

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.