Whose study of motion did Newton use to develop his first law of motion?

a. Galileo

c. Copernicus

b. Kepler

d. Ptolemy

Galileo's study of motion was used by Newton to develop his first law of motion. the correct option is option "a" among all the options that are given in the question. As per Newton's first law of motion, objects have the tendency of doing what it is continuously doing. there is a definite tendency among the objects in changing their states.