Jacobium is a radioactive metal with half life of 20 years. it contains 128 radioactive atoms. how many years will it take to decay to 2 radioactive atoms

N₀ = number of radioactive atoms initially present = 128

N = number of radioactive atoms left after time "t" = 2

t = time taken

T = half life period for the radioactive metal = 20 years

λ = decay constant = ?

decay constant is given as

λ = 0.693/T

inserting the values

λ = 0.693/20

λ = 0.0347

number of radioactive atoms left after time "t" is given as

N = N₀

inserting the values

2 = (128)

t = 120 years

the tires are rotating at 0.434 rpmlinear speed=45 m/sdiameter=0.550 mradius=0.275 mnow v= rωω= v/rω=45/0.275ω=163.6 rad/sω=163.6 rad/s (1rev/2π rad) (60s/1m)ω=1563 rpm