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Question
A cook used a ‘fire tong pair’ of length 32 cm. to lift a piece of burning coal of mass 500 g. If he applies his effort at a distance of 8 cm from the fulcrum, what is his effort? Assume friction etc. to be absent. Also, obtain values of the M.A. and the V.R. of this ‘machine’.
Solution
The ‘fire tong pair’ is a lever of class III in which the point of application of the effort is in between the load and the fulcrum. Hence, when friction, etc., are assumed absent, we have:
Effort × 8 cm = 0.5 kgf × 32 cm
Effort = `0.5 "kgf" × (32"cm")/(8"cm")`
= 2.0 kgf.
Thus, M.A. =`"Load"/"Effort"=0.5/2.0=1/4=0.25.`
Also, V.R. =`"Effort arm"/"Load arm"=(8"cm")/(32"cm")=0.25.`
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