The type of wave where particles in the medium experience forces parallel to the direction of wave propagation is a longitudinal wave.

Here's why:

* Longitudinal waves are characterized by the particles of the medium vibrating parallel to the direction the wave travels. This means the force on each particle is also parallel to the direction of wave propagation.

* Examples of longitudinal waves: Sound waves, seismic P-waves (primary waves)

In contrast, transverse waves have particles vibrating perpendicular to the direction of wave propagation. Examples include:

* Transverse waves: Light waves, electromagnetic waves, seismic S-waves (secondary waves)