2. who were the first philosophers to propose that atoms existed? what time period was
this?

"Greek Origins" were the first philosophers to propose that atoms existed.

Explanation:

The idea that all matter is made up of tiny, indivisible particles, or atoms, is believed to have originated with the Greek philosopher Leucippus of Miletus and his student Democritus of Abdera in the 5th century B.C. (The word atom comes from the Greek word atomos, which means “indivisible.”)

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle