Very Simple Angular Physics Problem

[chrispsu]

Hi there, brand new to the site. Came across it when googling for help on tangential velocity in a rotational problem.
Anyhow I have an online homework due at midnight and would love to have any help possible with this question before then.

Heres the problem...
The hour hand on a certain clock is 8.9 cm long. Find the tangential speed of the tip of this hand in µm/s.

I tried v= w(angular velocity)r
so v= 2pi*r/ (60)(60) and got 155.3µm/s

This however is incorrect and any help to lead me the right way is greatly appreciated :D

Im an A student in Physics but just don't grasp rotation as well as the other topics.
This question is probably very simple but it is just not clicking for me, maybe I am missing the correct formula to use?

 

[Noein]

How long does it take the hour hand of a clock to make one complete revolution?

 

[chrispsu]

How long does it take the hour hand of a clock to make one complete revolution?

3600 sec which is why i divided by that...is that not correct?

 

[Noein]

One hour is equal to 3600 s. This is not the total time it takes the hour hand to make one complete revolution, however.

 

[chrispsu]

One hour is equal to 3600 s. This is not the total time it takes the hour hand to make one complete revolution, however.

oh damn so i should multiplying 3600 * 24 then too!

see i knew i was making a dumb mistake, thanks a lot! :D

 

[Noein]

There are 24 hours in a day. But, when the hour hand of a clock goes around once, how many hours has it gone through?

 

[chrispsu]

There are 24 hours in a day. But, when the hour hand of a clock goes around once, how many hours has it gone through?

ahhh 12, tricky, tricky