InterviewSolution
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InterviewSolution
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A wooden crate with a heavy machine weighing3000 N slides on the ground when pushed by a lever AB of length100 cm as shownin the figure. The force required to slide the crate acts at a distance of 10 cm from the fulcrum . If the coefficient of friction betweenthe crate and the ground is sqrt(2), find the effort required to move the crate. (Take the value ofsqrt(2)=1.4) |
Answer» Solution :Different forces that act on thecrate are shown in the figure  Fromthe figure it is clear that R + L sin 45 = mg `R=[mg-(L)/(SQRT(2))]` and the force that is responsible forthe motionof the roller is L ` cos 45^(@)`. Thus, ` L cos 45^(@) = f = MU R rArr (L)/(sqrt(2))= mu (mg -(L)/(sqrt(2)))` `(L)/(sqrt(2))= mu mg.(mu L)/(sqrt(2)) rArr (L)/(sqrt(2))(mu + 1)=mu mg` Or ` L = (sqrt(2)mu mg)/(mu +1)` Now, (effort) (effort arm) = (load) (load arm) Effort `=(Lxxl)/(e)=(l)/(e) ((sqrt(2)mu mg)/(mu + 1))` GIVEN ` l=100 cm, e = 100 cm`, ` mg = 3000 N ` and `mu = sqt(2)` `=((10)/(100))((sqrt(2)xxsqrt(2)xx3000)/(sqrt(2)+1))=250 N` |
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