Question

A crowbar of length 2 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

Step 1:

Given data,

Load = 100 kgf,

Load arm = Distance between load to fulcrum $=0.1\mathrm{m}$.

Total length of crowbar $=2\mathrm{m}$,

Step 2:

Effort arm = Total length crowbar - load arm

Effort arm $2-0.1=1.9\mathrm{m}$

Step 3:

Formula:

$Mechanicaladvantage=\frac{Load}{Effort}=\frac{Effortarm}{Loadarm}$

Substitute the values in the above formula,

Mechanical advantage = $\frac{1.9}{0.1}=19$

Step 4:

$$\begin{gathered} Effort=\frac{Load}{Mechanicaladvantage} \\ Effort=\frac{100}{19}=5.26kgf \end{gathered}$$

Hence, the effort required to lift 100 kgf is 5.26 kgf.