a wave in which particles of the medium vibrate at right angles to the direction that the wave travels is called?

Explanation:

Longitudinal waves are waves in which the vibration of the medium is parallel to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure. 

In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.

Explanation:

hope it will help u

0.11 m/s and 0.28 m/s should be correct

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