The current theory of the structure of the Earth, called tectonic plates, tells us that the continents are in constant motion. Assume that the North American continent can be represented by a slab of rock 4400 km on a side and 35 km deep and that the rock has an average mass density of 2680 kg/m^3. the continent is moving at the rate of about 3 cm/year. part 1: what is the mass of the continent? answer in units of kg

part 2: what is the kinetic energy of the continent? answer in units of J

part 3: a jogger (of mass 69 kg) has the same kinetic energy as that of the continent, what would his speed be? answer in units of m/s

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

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.