Question

Calculate the force required to lift a load of $60\text{N}$, placed at a distance of $3\text{m}$ from the fulcrum, if the effort is applied at a distance of $6\text{cm}$ from the fulcrum.

• A. $300\text{N}$
• B. $3000\text{N}$
• C. $1500\text{N}$
• D. $30\text{N}$

Answer 1

The correct option is B $3000\text{N}$



$F_1=60\text{N},l_1=3\text{m},l_2=6\text{cm},F_2=?$
Left hand side moment, about fulcrum
$=60\times 3=180\text{Nm}$.
Right hand side moment about fulcrum $=F_2\times 6\times {10}^{-2}\text{Nm}$.
According to principle of moment,
$L.H.M=R.H.M$
$\Rightarrow 180=F_2\times 6\times {10}^{-2}$
$\Rightarrow F_2=\frac{180}{6\times {10}^{-2}}=3000\text{N}$
Therefore, a force of $3000\text{N}$ is required to lift the load.