A wheel of radius `20 cm` has four forces applied to it as shown in fig. Then, the torque produced by these forces about `O` is.
.

Options

A. `5.4 Nm` anticlockwise
B. `1.8 Nm` clockwise
C. `1.8 Nm` anticlockwise
D. `5.4 Nm` clockwise

Answer

B

Explanation

(b) Torque of `6 N` force will be zero. Net toque is
`tau_(n et) = 4 xx (20)/(100) -9 xx(20)/(100) -8 sin 30^0 xx (20)/(100) = -1.8Nm`
Negative sign shows that this torque will be clockwise.