The time it takes "to complete one cycle" is a perfect definition for <em>period</em>.
So the <em>2 sec</em> that you measured is the swing's period.
Frequency is just 1/period (the 'reciprocal' of the period).
For this swing, the frequency is 1/(2sec) = 0.5 per second = <em>0.5 Hz</em>.
( "Hertz" means "per second")
The invisible form is water vapor that is microscopic and found all around us. When the air is really hot you can see this water vapor above ground as if it's moving. The visible form is either water droplets that fall down as rain, or it's the clouds that are basically a form of moisture that is iced up because it's very cold so it condensed and formed a cloud.
You should draw a diagram of each for this question.
In a series circuit, the resistors experience the same current. In a parallel circuit, they have the same voltage drop. Therefore, the equivalent resistance is calculated differently for a series and parallel circuit.
Ohm's law: V=IR
Resistance keeps a circuit from shorting.
I am not sure if this is the answer you are looking for but a earthquake occurs when the plates shift.
Hope this helped.
