What led kepler to abandon circular orbits and his discovery that planetary orbits are ellipses?

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage

4. who was the first one to measure the speed of light and conclude that it is finite? 5. who was the first philosopher who thought the speed of light is finite? 13. what is the speed of light numerically? 14. give an example of something moving faster than light 15. give an example for some particles or waves that

Which of the following is the result of the nuclear weak force? the instability of large nuclei the repelling force between positively charged protons the structure of the atom certain types of nuclear decay