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Two small balls A and B of positive charge Q each and masses m and 2m, respectively, are connected by a nonconducting light rod of length L. This system is released in a uniform electric field of strength E as shown. Just after the release (assume no other force acts on the system) A. rod has angular acceleration `QE//2mL` in anticlockwise direction.B. rod has angular acceleration `QE//2mL` in anticlockwise directionC. acceleration of point A is `2QE//3m` toward rightD. acceleration of point A is `QE//m` toward right . |
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Answer» Correct Answer - A::D a.,d. Resultant force on arrangement is `2QE`, thus acceleration of center of mass is given by `a_(c)=2QE//3m`. Net torque on system is `QE((2L)/(3))=QE((L)/(3))=[mxx(4L^(2))/(9)+2mxx(L^(2))/(9)]a` `a=(QE)/(2mL` (clockwise) From constraint equation, we get `a_(A)=a_(c)+a((2L)/(3))` `=(2QE)/(3m)+(QE)/(2mL)((2L)/(3))=(3QE)/(3m)=(QE)/(m)` |
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