A) \[\theta =\frac{\pi }{4}\]
B) \[\frac{\pi }{4}<\theta <\frac{\pi }{2}\]
C) \[\frac{\pi }{2}<\theta <\frac{3\pi }{4}\]
D) \[\frac{3\pi }{4}<\theta <\pi \]
Correct Answer: D
Solution :
[d]: According to conservation of energy, \[\frac{1}{2}M{{v}^{2}}=\frac{1}{2}M{{\left( \frac{v}{2} \right)}^{2}}+Mgh\] \[\frac{1}{2}M5gL=\frac{1}{2}M\frac{5gL}{4}+MgL(1-cos\theta )\] or\[\cos \theta =-\frac{7}{8}\]or\[\theta ={{\cos }^{-1}}\left( \frac{-7}{8} \right)={{151}^{o}}\] \[\therefore \]\[\frac{3\pi }{4}<\theta <\pi \]You need to login to perform this action.
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