If the net work done on a particle is zero, which of the following statements must be true? A. The speed is unchanged.
B. The velocity is zero.
C. The velocity is unchanged.
D. More information is needed.
E. The velocity is decreased.

A. The speed is unchanged.

Explanation:

In the case when the work is to be done on a particle i.e. zero so the change made in KE of the particle would be zero. This represent the work energy theroem. But when the KE remains same or does not change so it should be the same and the particle speed would also the same

Therefore as per the given statement, the first option is correct

And rest of the options are wrong

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

its c i just checked it