clock question

xdem713o

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Sep 2, 2009
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The tip of the minute hand of a clock travels 3 cm in 15 seconds. Determine the length of the hand.

I know that the 15 seconds, is a 1/4th of a minute. I don't know it that would be pi/2. I know that 3cm would be s, which is the length of the arc. I'm confused becuase of the 15 seconds.
 


What is the angular velocity (?) of a clock's minute hand ?

We know that the linear velocity of the hand's tip is 3 cm per 15 seconds.

The angular velocity of the hand (?), the radius of the hand (r), and the linear velocity (v) are all related by the following formula.

v = r * ?

Substitute values for v and ?, and then solve for r.

 
xdem713o said:
Is the angular velocity of the minute hand 2pi/hour?


If you're trying to say 2Pi radians/hour, then YES.

But, in this exercise, the given time units are seconds.

Can you convert radians/hour to radians/second ?

 
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