That particular group of elements is reffered to as the "Noble Gasses"--a title that comes from the fact that these gases are very "secure" and don't mix well with other elements.
Oxygen. Plants need water sunlight and CO2 to make their food. They get the carbon and the energy from the CO2 and the sun, and they need water as well. Then they release oxygen
The answer is 2500 newtons. F = M * A, so 500 kg x 5 m/s = 2500 newtons.
Voltage = current x resistance
since R is doubled, current must reduce by half.
So,
new current = 120/2 = 60mA
