A fire tongs has its arms 20 cm long. It is used to lift a coal of weight 1.5kgf 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.

Solutions:

According to the question,

Length of arms of fire tong is 20 cm

Effort arm is 15 cm long and the length of Load arm is 20 cm

(i) Expression for the Mechanical advantage is

M.A. = Effort arm / Load arm = 15 / 20

M.A. = 0.75

(ii) Expression for Effort is

Effort = Load / M.A = 1.5 / 0.75

Effort = 2.0 kgf