CBSE Class 9 Answered

If one end of a thin long stretched rubber tube is tied to a hook on the wall and the free end is given jerk up or down, we see that the jerk travels to the fixed end through the tube but the particles of the tube (medium) do not move ahead.

Actually due to jerk at one end of the tube, its particles are displaced from from their mean positions. Since each particle of the tube is bound with a tensile force with the nearest particle , if a particle is displaced its nearest particle also gets displaced and this is how the disturbance moves throughout the tube. The particles of the tube (medium) do not move ahead, only the energy is transferred  from one end to the other by the pulse.