The radioactive element polonium decays according to the law given below where Q0 is the initial amount and the time t is measured in days. Q(t) = Q0 · 2-(t/140) If the amount of polonium left after 560 days is 80 mg, what was the initial amount present?

1280 mg

Explanation:

Radioactive  decay is a phenomenon that occurs when a certain isotope of an element, said to be radioactive, decays, turning into a lighter nucleus and emitting radiation + energy in the process.

The radioactive decay of this isotope of polonium is described by the equation

where

is the amount of polonium left after time t

is the amount of polonium t time t = 0

is the half-life of the polonium, in days (it is the time it takes for the initial element to halve its amount)

IN this problem, we know that:

After t = 560 days, the amount of polonium left is . Therefore, we can re-arrange the equation, substituting t = 560 d, and solve for to find the initial amount of polonium:

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

we need to know the time interval during which the force acts. impulse of force = momentum change