Question

The 4.5 cm long second hand on a watch rotates smoothly. What is its angular velocity? What is the speed of the tip of the hand?

Answer 1

Angular velocity means how many radians/degrees is this hand passing by every second.
First, you realize it goes through a whole revolution (2
`\pi` in radians) in 60 seconds.
This means for every second, it passes by:

`(2 \pi )/(60 s) = 0.105 (rad)/(sec)`

For the next part, you need to know this equation:
Tangential velocity=Angular velocity x radius (meters)

`velocity=0.105 (rad)/(sec) *0.045m`

`velocity=0.004725 (meters)/(sec)`