The rotational effect is produced by

$A$ person supports a book between his finger and thumb as shown (the point of grip is assumed to be at the corner of the book). If the book has a weight of $W$,then the person is producing a torque on the book of

$A$ solid cone hangs from a frictionless pivot at the origin $O$,as shown. If $\hat{i}$,$\hat{j}$,and $\hat{k}$ are unit vectors,and $a, b$,and $c$ are positive constants,which of the following forces $\vec{F}$ applied to the rim of the cone at a point $P$ results in a torque $\vec{\tau}$ on the cone with a negative $z$-component $\tau_z$?

$A$ slab is subjected to two forces $\vec F_1$ and $\vec F_2$ of the same magnitude $F$ as shown in the figure. Force $\vec F_2$ is in the $XY$-plane,while force $\vec F_1$ acts along the $z$-axis at the point $(2\hat i + 3\hat j)$. The moment of these forces about point $O$ is:

Find the torque of a force $\overrightarrow F = 2\hat i + \hat j + 4\hat k$ acting at the point $\overrightarrow r = 7\hat i + 3\hat j + \hat k$.

$A$ force $F = 2.0\,N$ acts on a particle $P$ in the $xz-$ plane. The force $F$ is parallel to the $x-$ axis. The particle $P$ (as shown in the figure) is at a distance $3\,m$ from the origin,and the line joining $P$ with the origin makes an angle of $30^\circ$ with the $x-$ axis. The magnitude of the torque on $P$ with respect to the origin $O$ (in $N-m$) is: