Is elasticity a property of a sound wave

Elasticity is involved whenever atoms vibrate, so yes it is an example of movement of a sound wave.

The sound wave travels more rapidly through the steel of the track than through the air, because the elastic modulus of steel is a million times greater than the bulk modulus of air.

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day