In the following diagram, the counter-clockwise torque is equal to

10 nm
80 nm
400 nm
500 nm

400 Nm

Explanation:

Moments are given by multiplying force and distance

Taking moments where the pivot is locate

The counter-clockwise moment is given by 100*5= 500 Nm (It moves against the normal direction of the clock considering the pivot location)

Clockwise moments is given by 40*2= 80 Nm (Moment moves in the direction of clock considering pivot location)

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