# How do I express the frequency of the hour hand? (1 Viewer)

### Users Who Are Viewing This Thread (Users: 0, Guests: 1)

#### LoveKnowledge

I know that in a second it is 1/60 Hz. In a minute it is 1/3600 Hz. How do I express it in hour hand? I am a little confused.

#### LoveKnowledge

I don't just want the answer, also the explanation so that I know! I am just a little confused...thx

#### LoveKnowledge

I think 1/43,200 Hz? But I am just a little confused with the explanation.

#### russ_watters

Mentor
You're not making any sense. Hz is cycles per second. So how many cycles per second do you have (of what?)? Per hour?

 er - I missed the title....you shouldn't need any math to do the frequency (revolutions?) of the hour hand per hour. And then you can go from there to the other two.

Last edited:

#### stevenb

I think 1/43,200 Hz? But I am just a little confused with the explanation.
Your answer is correct. The cyclic frequency in Hertz is just the reciprocal of the period in seconds. (f=1/T)

Here T=43200 seconds which is the time it takes the hour hand to go around once, which it does in 12 hours, of course.

There is not much explanation that one can give other that to consider the definition of frequency in Hz as cycles per second.

Other units for frequency include revolutions per minute RPM and radians per second, angular frequency.

The hour hand also spins at 1/720 RPMs.

Of course, you are free to make up your own units, and expressing frequency as 2 cycles per day might not be a bad idea.

### The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving