Question

Find the net torque (in Nm) on the wheel in figure about the point $O$ if $a=10cm$ and $b=25cm.$ Round off to the closest integer.

Answer 1

${\tau }_{10N}=10\times 0.25$
$=2.5Nm$(clockwise)
${\tau }_{9N}=9\times 0.25$
$=2.25Nm$ (clockwise)
${\tau }_{12N}=(12\cos {60}^{\circ }\times 0.1)$
$=0.6N$ (anticlockwise)
$\therefore {\tau }_{net}=4.15Nm$
When rounded off to nearest integer it is 4 Nm.