InterviewSolution
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InterviewSolution
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Find the ratio of effortsrequired to raise a given load, when the angle of inclination of a given plank is changed from 60^(@) to 30^(@). Also find the percentage change in the mechanical advantage. |
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Answer» SOLUTION :The ratio of efforts `((E_(1))/(E_(2)))` is `(E_(1))/(E_(2))=(mg SIN theta_(1))/(mg sin theta_(2)) rArr (E_(1))/(E_(2))=(sin theta_(1))/(sin theta_(2))` Substituting ` sin 60^(@)=(sqrt(3))/(2)` and ` sin 30^(@)=1//2`, we get `(E_(1))/(E_(2))=(sqrt(3))/(2)xx2=sqrt(3)` `:.E_(1):E_(2)= sqrt(3):1` Change in M.A. ` = (1)/(sin 30^(@))-(1)/(sin 60^(@))=2-(2)/(sqrt(3))` `=2(1-(1)/(sqrt(3)))=2((sqrt(3)-1)/(sqrt(3)))` % Change in MA =`("Change in MA")/("INITIAL MA")xx100` `=(2 (sqrt(3)-1))/(sqrt(3)xx(2)/(3))xx100=(sqrt(3)-1)xx100` `= 0.732xx100=73.2%` |
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