density is correct hope this helps
The statement is false. Vectors are used to solve projectile motion problems because they allow the analysis of one direction at a time for two-dimensional motion. Scalar quantities can be used to analyze linear motion problem, but not projectile motion.
3, protons are positive and there are 3 positive atoms visible
Answer:
Let No be initial no of atoms
N = N0 / 2 after 1 half-life
N = N0 / 4 after 2 half-lives
So after 2 half-lives 20 of the 80 atoms remain