Compound or a simple element.
For example O2 is a chemical formula and represents the element oxigen, because it exists as a diatomic molecule in the air.
NaCl is a chemical formula and represents sodium chloride
CH4 is a chemical formula and represents methane.
Hubble noticed that the galaxies were moving away from us, which meant the universe was expanding.
This is why constellations change over time. In some years, the Big Dipper won't actually look like a dipper anymore.
The masses of the object and the planet it's on, and the distance between their centers.
Answer:
The ball took 0.4 seconds
Explanation:
» From the second newton's equation of motion.

- s is displacement, s = 80cm, s = 0.8 meters
- u is initial velocity, u = 0 [ from rest ]
- g is 10 m/s²
