Here's why:
* Transverse waves involve oscillations perpendicular to the direction of energy propagation. Imagine a rope tied to a post. If you shake the rope up and down, you create a wave that travels along the rope horizontally. The energy of the wave moves horizontally, while the rope itself oscillates vertically.
* Longitudinal waves involve oscillations parallel to the direction of energy propagation. Think of a slinky. If you push and pull the slinky, you create a wave that travels along the slinky. The energy of the wave moves in the same direction as the slinky compressions and expansions.
Therefore, transverse waves are the waves that transmit energy in a definite direction and with speed due to their perpendicular oscillations.
