Question

The length of hour hand of a wrist watch is 1.5 cm. Find magnitude radial acceleration.
(Ans : 3.175 x 10⁻¹⁰ m/s²)

Answer 1

The length of hour hand of a wrist watch is 1.5cm, r = 1.5cm.
for hour hand, $T_H$ = 12hr = 12 × 60 × 60 sec = 43200 sec
angular velocity, $\omega=\frac{2\pi}{T_H}$
= 2π/(43200)
= 1.455 × 10^-4 rad/s

radial acceleration, $\alpha=\omega^2r$

= (1.455 × 10^-4)² × 0.015 m/s²

= 3.175 × 10^-10 m/s²