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प्रश्न
Fig shown a block and tackles system of pulleys used to lift a load.
(i) How many strands of tackle are supporting the load?
(ii) Draw arrows to represent tension in each stand.
(iii) What is the mechanical advantage of the system?
(iv) When load is pulled up by a distance 1 m how far does the effort end move?
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उत्तर
(I) 4 stands of tackle are supporting the load.
(ii) correct winding of rope around pulleys, load and effort is as shown:
(iii) M .A = L/E
here,L = 4T, E = T
M.A = `(4"T")/"T"` = 4
(iv) since there are four strings in the block and tackle system, therefore, the velocity ratio of the system is V.R = n = 4
Now, V.R `"d"_"E"/"d"_"L"`
or, `"d"_"E" = 4 xx "d"_"L" = 4 xx 1 = 4"m"`
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What is a pulley?
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(i) State, how many strands of tackle support the load?
(ii) Draw arrows to represent tension in each strand.
(iii) Find the mechanical advantage of the system, stating the assumptions made.
(iv) If the load is pulled up by a distance 1m, how much does the effort end move?
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