How do scientific models provide a practical solution for some types of research

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?

Why does the earth spin slowly, not faster? is it possible to prove it scientifically? can you prove it with math?

9. what area of study applies scientific findings to create ways for solving problems or improving life? a biogeology b mathematics c manufacturing d engineering