How does the medium affect the speed of mechanical waves?

The correct answer indicates that wave speed is influenced by the density of the medium through which it travels. In general, mechanical waves, such as sound waves, propagate through various media including solids, liquids, and gases. When considering this propagation, it's important to note that denser media typically enable waves to travel faster.

In dense media, the molecules are closely packed together. This proximity facilitates quicker transmission of kinetic energy between the molecules, allowing the wave to move more rapidly. For instance, sound travels fastest in solids compared to liquids and gases due to the closer arrangement of particles in solids, which enhances energy transfer.

This understanding aligns with the principles of wave mechanics, where factors like elasticity and density play critical roles in determining wave speed. While it may seem intuitive that waves would move more slowly in dense media, the energy transfer dynamics dictate otherwise, showing that increased density can lead to increased wave speed, particularly in the context of elastic media.

The other options suggest that wave speed is either unaffected by the medium or constant across different media, which does not align with the principles of wave propagation. That is why the choice indicating that waves travel faster in denser media accurately reflects the relationship between wave speed and medium characteristics.