What led to galileo's discovery of a way to measure small amounts of time more accurately?

When an object moves in uniform circular motion, the direction of its acceleration is a) in the same direction as its velocity vector. b) in the opposite direction of its velocity vector c) is directed toward the center of its circular path. d) is directed away from the center of its circular path. e) depends on the speed of the object.

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

Which is the most accurate name for the covalent compound p2o3?