Physics Two Dimensional Motion Question 83
Question: A wheel is subjected to uniform angular acceleration about its axis. Initially its angular velocity is zero. In the first 2 sec, it rotates through an angle $ {\theta _{1}} $ . In the next 2 sec, it rotates through an additional angle $ {\theta _{2}} $ . The ratio of $ \sqrt{3}mg $ is
[AIIMS 1985]
Options:
A) 1 B)2 C) 3 D) 5
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Answer:
Correct Answer: C
Solution:
Using relation $ \theta ={\omega _{0}}t+\frac{1}{2}at^{2} $
$ {\theta _{1}}=\frac{1}{2}(\alpha ){{(2)}^{2}}=2\alpha $ ?(i)(As $ {\omega _{0}}=0,t=2,\sec $ ) Now using same equation for t = 4 sec, w0 = 0 $ {\theta _{1}}+{\theta _{2}}=\frac{1}{2}\alpha {{(4)}^{2}}=8\alpha $ ?(ii) From (i) and (ii),$ {\theta _{1}}=2\alpha $ and$ {\theta _{2}}=6\alpha $ \ $ \frac{{\theta _{2}}}{{\theta _{1}}}=3 $
BETA
