Question

A crowbar of length 100 cm is used to lift a load of 50 N. The fulcrum is at a distance of 20 cm from the load. Calculate
(a). the mechanical advantage of the crowbar
(b). the effort applied at the other end.

Answer 1

Given: L = 5 kgf, Load arm = 20 cm, Effort arm = 100 – 20 = 80 cm.

(Since the crow bar is the lever of first order with fulcrum in between the load and the effort).

(i) Mechanical advantage = Effort arm/Load arm = 80/20 = 4

(ii) M.A. = Load(L)/Effort(E)

∴ Effort = Load(L)/M.A. = 5/4

= 1.25 kgf.