Physics

A fire tongs has its arms 20 cm long. It is used to lift a coal of weight 1.5 kgf by applying an effort at a distance 15 cm from the fulcrum.
Find:
(i) the mechanical advantage of fire tongs and
(ii) the effort needed.

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We know that,

$\text{Mechanical advantage M.A.} = \dfrac{\text{Effort arm}}{\text{Load arm}} \\[0.5em]$

Given,

Load arm = 20 cm

Effort arm = 15 cm

Substituting the values in the formula we get,

$M.A. = \dfrac{15}{20} \\[0.5em] \Rightarrow M.A. = 0.75 \\[0.5em]$

(ii) We know that,

$\text{Effort} = \dfrac{\text{Load}}{\text{M.A.}} \\[0.5em]$

Given,

Load = 1.5 kgf

Substituting the values in the formula we get,

$\text{Effort} = \dfrac{1.5}{0.75} \\[0.5em] \Rightarrow \text{Effort} = 2 \text{ kgf} \\[0.5em]$

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