Question

A crow bar 3 m long supported on a stone lifts a load of 150 kgf. If effort applied is 30 kgf, find the distance of the support from the load.​

Answer 1

Explanation:

Length of crow bar = 2m

length of load arm = 0.1 m

length of effort arm = length of crow bar - length of load arm

= 2 - 0.1 = 1.9m

so, velocity ratio = length of effort arm/length of load arm = 1.9/0.1 = 19

use formula, velocity ratio = load/effort

19 = 100kgf/effort

effort = 100/19 = 5.26 kgf

hence, 5.26 effort is required.