Aradioactive polonium sample has a half-life of 103 years. how much of a 100 g sample would remain after 412 years?

6.25 g

Explanation:

The half-life of a radioactive isotope is the time needed for the mass of the sample to halve.

Here, we a radioactive polonium sample, whose half-life is

The mass of sample left after a time t is given by the equation

where

is the initial mass

is the half-life

If we substitute t = 412 y , we find the mass of sample left:

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg

there are no contact forces mentioned on the list of choices that you've provided.