InterviewSolution
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InterviewSolution
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Two pendulums at rest swinging together. Their lengths are respectively `1.44 m` and `1 m`. They will again start swinging in same phase together after (of longer pendulum) : A. `1` vibrationB. `3` vibrationsC. `4` vibrationsD. `5` vibrations |
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Answer» Correct Answer - D Let `x_(1) = A_(1)sinomega_(1)t` and `x_(2) = A_(2)sinomega_(2)t` Two pendulums will vibrate in same phase again when there phase difference `(omega_(2) - omega_(1))t = 2pi` `rArr ((2pi)/(T_(2)) - (2pi)/(T_(1)))t = 2pi` `rArr (sqrt((g)/(1)) - sqrt((g)/(1.44)))n xx T_(1) = 2pi` (where `n` is number of vibrations completed by ionger pendulum) `rArr (sqrt((g)/(1)) - sqrt((g)/(1.44)))n xx 2pisqrt((1.44)/(g)) = 2pi rArr n = 5` Thus after `5` vibrations of longer pendulum they will again start swinging in same phase. |
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