Rotational Motion Question 219
Question: A thin ring, a disk and an annular cylinder, of same mass M, are released from a point 3.6m from the ground up an inclined plane of $30{}^\circ $ degree inclination. The ring and the disk have the same radius R. Times taken by the ring and disk to reach the ground are in the ratio,
Options:
A) $\sqrt{2}:\sqrt{1.5}$
B)$\sqrt{1.4}:\sqrt{1.5}$
C) $\sqrt{1.5}:\sqrt{1.5}$
D)$\sqrt{1.5}:\sqrt{1.6}$
Show Answer
Answer:
Correct Answer: A
Solution:
[a]
$t=\frac{1}{\sin }\theta \sqrt{\frac{2h}{g} 1+\frac{K^{2}}{R^{2}}}\Rightarrow t\propto ( 1+\frac{K^{2}}{R^{2}} )$
$so,t _{1}:t _{2}=\sqrt{2}:\sqrt{1.5}$
