Fallacies can be spread by companies or even people who want to sell a product for profit (money). They can also be spread on accident or on purpose by people who misunderstand the concept.
I would say 2nd law. Go over this with your teacher though
If it takes the swing 2 seconds to complete one cycle, then
that's the period of its motion ... 2 seconds.
The frequency is the reciprocal of the period ... 1/2 Hz.
('Hz' means 'per second'.)
I would use meter and second.
Hope this helps.
You can't change time to a measurement of distance
