Question

The length of hour hand of a wrist watch is 1.5 cm. Find magnitude of angular velocity.
(Ans : 1.454 x 10⁻⁴ rad/s)

Answer 1

Length of hour hand of a wrist watch is 1.5cm.
we know,
$\qquad\omega=\frac{2\pi}{T}$
where T is the time taken to complete one circle by hour hand, $\omega$ is the angular velocity of hour hand.

T = 12 × 60 × 60 sec
= 43200 sec

$\omega=\frac{2\pi}{12\times60\times60}\\\\=\frac{\pi}{21600} rad/s\\\\=0.00014537037 rad/s$

$\omega=1.454\times10^{-4} rad/s$