Question

A crow bar of length 2.0 m is used as a machine to lift a box of 100 kgf by placing a fulcrum at a distance of 0.1 m from the box. Calculate the effort required.

Answer 1

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.

Answer 2

Solution :-

Length of crow bar = 2.0 m

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 kg/f ans.
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@GautavSaxena01