There's nothing mysterious about it at all. "Frequency" simply means
"often-ness" ... how often or how frequently something happens.
-- The frequency of traditional meals is 3 per day.
-- The frequency of an equinox is 2 per year.
-- The frequency of my sleeping really late is 1 per week.
-- The frequency of my intense desire to sleep late is 30 per month.
etc.
-- The standard unit of frequency in the SI system is "per second".
The special name for that unit is "Hertz". (Hz)
Answer:

Explanation:
Since the hoop is rolling on the floor so its total kinetic energy is given as

now for pure rolling condition we will have

also we have

now we will have


now by work energy theorem we can say



now solve for final speed

I have a formula here that might just help you solve the problem on your own:
The number of images depends on the angle between the two mirrors. The number of images formed in two plane mirrors inclined at an angle A to each other is given by the formula:
Number of images = 360<span>/A - 1.
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I hope my guide has come to your help. God bless and have a nice day ahead!
That was Tycho Brahe, and I thought it was actually more years than that.