In an ideal block and tackle with 5 strings supporting the load, the effort needed to lift 1000 N is:
A500 N
B200 N
C100 N
D1000 N
Answer & Solution
Correct answer: B. 200 N
1. M.A. of an ideal block and tackle = number of strings supporting the load.
2. M.A. = 5.
3. Effort = load / M.A. = 1000 / 5 = 200 N.
4. So the effort needed is 200 N.
_Source: Selina Concise Physics ICSE Class 10, Ch 3 'Machines' (aplustopper.com extract)_
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