Find equivalent resistance??

Req = 50 Ω

Explanation:

The equivalent resistance is basically the sum of all the resistances in a circuit.

The sum of these resistances will depend whether these resistance are in series or parallel.

If the resistances are on series, the expression to use is:

R = R₁ + R₂ + R₃ + Rₙ   (1)

If the resistances are on parallel then the expression to use is:

1/R = 1/R₁ + 1/R₂ + 1/Rₙ    (2)

Now, according to the picture, we have R₁ and R₄ in series, so here we have to use (1):

R₁₄ = 10 + 30 = 40 Ω

R₂ and R₃ are in parallel so we use (2):

1/R₂₃ = 1/20 + 1/20 = 2/20 = 1/10

R₂₃ = 10 Ω

Finally, R₁₄ and R₂₃ are in series (Because of the sum of the resistance in each side, they are now forming one resistance in each side), therefore, we use (1) again to get the equivalent resistance of the whole circuit:

Req = 10 + 40

Hope this helps

answer: b.

explanation:

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