Question

do mechanical waves lose energy as they travel through a medium? Why/why not?

Answer 1

Yes,

As it travels, a mechanical wave's energy is slowly lost as heat. This happens because the molecules of the medium through which it is travelling knock against each other as they transmit the mechanical wave energy.

Because a gas, such as the air, presents less friction to a mechanical wave than a solid, it can travel a longer distance before all it's energy is lost.