I am pretty sure that the only statement which is true for particles of the medium of an earthquake P-wave is being shown in the option : b)vibrate parallel to the wave, forming compressions and rarefactions. As you know, <span> it can be formed in two ways : from alternating </span>compressions<span> and </span>rarefactions<span> or </span><span>primary wave. I bet you will agree with me.</span>
The statement is true for particles of the medium of an earthquake P-wave is : They vibrate in a direction parallel to that of the wave, forming compression and rarefaction P-waves can be produced by earthquakes and recorded by seismographs.
All of the frictions are the same, but weight always goes straight down so it can only be A or B. Since they are going down a slope, then the normal force must be sloped. A is the only one out of A and B with a sloped normal force, so it has to be A
