15. D is correct, exothermic reactions release heat
I am not sure about 16
Answer:
4m/s in the direction of the turn
Explanation:
The velocity of an object is the rate of change of its position with respect to a frame of reference.
Assuming the runner stays the same speed as he turns, his velocity will be 4m/s in the speed he turns.
Its atomic symbol is H and its atomic number is one. Hydrogen; Hydrogen, H, is a chemical element with atomic number 1. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H2.
Hydrogen is easily the most abundant element in the universe. It is found in the sun and most of the stars, and the planet Jupiter is composed mostly of hydrogen. On Earth, hydrogen is found in the greatest quantities as water.
