Question

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 of 15 cm from the fulcrum. Find : (i) the mechanical advantage of the fire tongs , and (ii) the effort needed.

• A. M. A = 0.45 Effort = 9 Kgf
• B. M. A = 0.45 Effort = 6 Kgf
• C. M. A = 0.45 Effort = 2 Kgf
• D. M. A = 0.75 Effort = 2 Kgf

Answer 1

The correct option is D

M. A = 0.75

Effort = 2 Kgf

Effort arm = 15 cm

Load arm =20 cm

(i) Mechanical advantage

(ii) Effort = $\frac{Load}{MA}=\frac{1.5}{0.75}=2kgf$