Re: Re:
xdem713o said:
mmm4444bot said:
xdem713o said:
… I know the answer is pi/360 rad/min. Looking at this, I know that the 360 is perahps coming from the 360 degrees … in one revolution.
If this seems daunting, then try (1) realizing that an hour hand revolves once in 24 hours, and (2) calculating the corresponding number of minutes. Use the total number of minutes to determine the fractional part of one revolution (in one minute).
What do you mean by saying an hour hand revolves once in 24 hours?
Actually, I think the hour hand revolves once in 12 hours.
For example, if the hour hand is on 1, it will be back there again in 12 hours (if we are dealing with a standard clock...not a military clock).
So, the hour hand moves through one revolution in 12 hours.
12 hours is 12*60 minutes, or 720 minutes.
If the hour hand makes 1 revolution in 720 minutes, then it makes 1/720 revolutions per minute.
Now, does that make sense? Suppose you think about the movement of the hour hand in ONE hour. If the hour hand is on 1, it will be on 2 one hour later, right? The hour hand will have moved 1/12 of the way around the circular clock. And, if we've determined that the hour hand moves 1/720 revolutions per minute. Ok...in 1 hour (60 minutes) how far would the hour hand move? Well, it would be 60/720 revolutions, or 1/12 revolutions...which would put the hour hand ONE HOUR past where it was to begin with.
If you want radians per minute, then remember that 2 pi radians = 1 revolution.
So 1/720 revolutions per minute = (1 revolution/720 minutes)*(2 pi radians/revolution) = 1 pi radian / 360 minutes
Or, pi/360 radians/minute