Question

The 8.50-cm-long second hand on a watch rotates smoothly.

What is the speed of the tip of the hand?

please include correct units

Answer 1

speed of the tip of the hand= tangential velocity = angular velocity * radius

First, we need to find teh angular velocity:

Angular velocity basically means the number of radians covered in a second

The second hand goes through 2$\pi$ radians in 60secs

so, angular velocity = 2$\pi$/60 = 0.105rad/sec

Therefore, tangential velocity = 0.105*8.5*10^-2 =8.9*10^-3m/s