Question

Four forces are applied to a wheel of radius $20$ cm as shown in figure. The net torque produced by the forces is

• A. 5.4 Nm anticlockwise
• B. 1.8 Nm clockwise
• C. 2.0 Nm clockwise
• D. 5.4 Nm clockwise

Answer 1

Answer: (B)

1.8 Nm clockwise

$\overline{c}=(\overrightarrow{r}\times \overrightarrow{f})$

There are 4 forces in picture.

So, total Torque = Trq_A + Trq_B + Trq_C + Trq_D
Trq${}_{tot}=\left(\right(8\times r\times \frac{1}{2})-(r\times 4)+(9\times r)+0)$
Trq ${}_{tot}$ = 9r $\left(clockwise\right)$
Trq${}_{tot}$ = $\frac{9\times 20}{100}$
Trq${}_{tot}$ $=1.8Nm$ clockwise