Why does a straw look broken viewed in a glass of water?

This is due to refraction of light

Explanation:

When a straw is placed in a glass it appears to be broken as a result of refraction of light on the air-water interface.

Since, the refractive index of water is more than that of glass.

Also, water is denser than air, which means light travels slower in water than in air.

Most importantly, When light travels from rarer to denser medium it bents towards the normal and deviates from its original path which explains the broken view of straw in a glass of water.  

i don't know that i agree with that but what's the question ?

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