Question

A 2 kg mass is rotating on a circular path of radius 0.8 m with angular velocity of 44 rad/sec. If radius of path becomes 1 m. Then the value of angular velocity will be:

• A. 28.16 rad/sec
• B. 35.16 rad/sec
• C. 19.28 rad/sec
• D. 8.12 rad/sec.

Answer 1

Answer: (A)

28.16 rad/sec

Answer 2

Angular momentum,

L=mr2w = constant

$\frac{\omega_{2}}{\omega_{1}} = \left( \frac{r_{1}}{r_{2}} \right)^{2} = ⥂ \left( \frac{0.8}{1} \right)^{2}$=0.64⇒$\omega_{2} ⥂ = ⥂ 44 \times 0.64 = 28.16\mspace{6mu}\frac{rad ⥂}{s}$