1. At a certain instant, a piece of radioactive material contains 10^12 atoms. The half-life of
the material is 30 days
1. Calculate the number of disintegrations in the
first second.
2.How long will elapse before 10^14 atoms remain?
3. What is the count rate at this time?​

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?