InterviewSolution
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InterviewSolution
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Figure shows a system of four pulleys with two masses `m_(A) =3kg` and `m_(B)=4 kg`. At an instant force acting on block A if block `B` is going up at an acceleration of `3 m//s^(2)` and pulley `Q` is going down at an acceleration of `1 m//s^(2)` is .A. `7N` acting upwardB. `7N` acting downwardC. `10.5 N` acting upwardD. `10.5 N` acting downward |
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Answer» Correct Answer - D Writing constraint for the string `2x_(A) +2x_(B) -x_(Q) +k =l` Differnting twice w.r.t time `2a_(A)+2a_(B) -a_(Q)=0` Taking downward direction to be positive `2a_(A)+2(-3) -1 =0, 2a_(A) =7, a_(A) =3.5 m//s^(2)` Positive sign indicates that block is acceleration at `3.5m//s^(2)` in downward direaction. So, force acting `F =3 xx 3.5 =10.5 N` (downward) . |
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