Strontinum-90 is produced as a nuclear fission product of uranium in both reactors and atomic
bombs. It has too many neutrons, and it decays
with a half-life of about 29 yr.

(need help with a and b)

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? how far will the football travel before it lands?

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.

Consider an ideal gas at 27.0 degrees celsius and 1.00 atmosphere pressure. imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube. what is the length l of an edge of each small cube if adjacent cubes touch but don't overlap?