A boy can apply effort of 100 N. If he wants to lift a 400 N load, the M.A. of the machine he needs is at least:
A2
B3
C4
D5
Answer & Solution
Correct answer: C. 4
1. M.A. = load / effort = 400 / 100.
2. M.A. = 4.
3. So he needs a machine of M.A. at least 4.
4. Anything less would mean his 100 N effort cannot lift the 400 N load.
_Source: Selina Concise Physics ICSE Class 10, Ch 3 'Machines' (aplustopper.com extract)_
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