One of the most startling cosmological discoveries made recently is of course the realization that the rate of expansion of the universe is increasing. this realization gave a new life to the cosmological constant that einstein once called one of the biggest blunders he made. suppose that future astrophysicists make yet another startling discovery that the rate of expansion of the universe stopped increasing and turned around to start decreasing. in such a circumstance, make a sound physical argument about the nature of the cosmological constant based on this hypothetical new discovery. (hint: what are the critical quantities that determine the rate of expansion of the universe? )

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

inverse v=i*r

nice nice

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.