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