Question

A nut is opened by a wrench of length $20cm$. If the least force required is $2N$ ,find the moment of force needed to loosen the nut .

Answer 1

Step 1: Given data,

Force$\left(F\right)$, required = $2N$

Distance$\left(D\right)$ =$20cm$$=\frac{20}{100}=0.2m$ (we changed cm to m because the S.I unit of moment of force is N m)

Step 2:

$MomentofForce\left(\tau \right)=force\times perpendiculardis\tan cefromtheaxisofrotation$

$$\begin{gathered} \Rightarrow \left(\tau \right)=0.2m\times 2N \\ \Rightarrow \left(\tau \right)=0.4Nm \end{gathered}$$

Hence, A moment of force$\left(\tau \right)$ needed to loosen the nut is $0.4Nm$.