Answer:
They are the only joints that can do 360 degrees and rotate with their own axis. But, because of its free-moving, it is prone to any dislocation compared to other movable joints.
Explanation:
'Frequency' is a word that often confuses some people ... for no good reason.
It just means "frequent-ness" or "often-ness" ... how often something happens.
The SI unit of frequency is the Hertz (Hz). Hz means 'per second'.
So " 13 Hz " means 13 per second.
Here are examples of frequency:
-- 780 kilohertz (on your AM radio dial)
-- 98.7 Megahertz (on your FM dial)
-- 5.8 Gigahertz
-- twice a day
-- three per week
-- every 6 months
1) Because you have a lower chance of getting electrocuted, 2) 1.DON'T plug a bunch of stuff into one outlet or extension cord, 2.Make sure all electric cords are tucked away neatly, 3.DON'T ever climb the fence around an electrical substation, 4.DON'T yank an electrical cord from the wall, 5.Keep electrical stuff far away from water, 6.Ask a grown-up for help. 3) <span>Always determine if there is power to a circuit or wire using a voltmeter. Never touch any part of a circuit if you did not verify yourself that the the power is off(disconnected). { Trust but verify :President R. Reagan} Having turned off or disconnected the power assure that it cannot be accidentally turned on again by another person. Your Welcome.</span>