Question

The 7.00-cm-long second hand on a watch rotates smoothly. Part A What is its angular speed? Express your answer in radians per second to three significant figures rad/s Submit ▼ Part B What is the speed of the tip of the hand? O Type here to search

Answer 1

The second hand in a watch completes one revolution in 60 seconds.

Time period for one revolution = T = 60 sec

Angular speed of the second hand = $\omega$

$\omega = \frac{2\pi }{T}$

$\omega = \frac{2\pi }{60}$

$\omega$ = 0.105 rad/s

Length of the second hand = L = 7 cm = 0.07 m

Speed of the tip of the second hand = V

V = $\omega$L

V = (0.105)(0.07)

V = 7.35 x 10^-3 m/s

a) Angular speed of the second hand = 0.105 rad/s

b) Speed of the tip of the hand = 7.35 x 10^-3 m/s