Atoms with certain characteristics are radioactive. Which is least likely to be
radioactive?
A. all atoms with an atomic number under 40
B. all atoms with an atomic number over 83
C. all atoms with twice as many neutrons as protons
C
D. all atoms with half as many neutrons as protons

choosing tennis and golf balls is your inde choice.

their mass and volume are dep

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

+15-35=-20

going in opposite directions