What kind of waves do you think will travel along a horizontal metal rod if you strike its end (a) vertically from above and (b) horizontally parallel to its length?
(a) If you strike a horizontal rod vertically from above, the particles will vibrate in the vertical direction. Based on the length of the rod, there will standing waves, nodes and antinodes. The up and down motion will also create sound waves which travel along the length
(b) If you strike the same horizontal rod parallel to its length longitudinal sound waves will be created parallel to the rod length. The particles will also move along the lenght of the rod.