Which type of motion exists due to the moment of force (couple)?

When a force of $6.0 \, N$ is exerted at $30^{\circ}$ to a wrench at a distance of $8 \, cm$ from the nut,it is just able to loosen the nut. What force $F$ would be sufficient to loosen it,if it acts perpendicularly to the wrench at $16 \, cm$ from the nut (in $, N$)?

What is the torque of a force $\vec{F} = 3\hat{i} + 7\hat{j} + 4\hat{k}$ about the origin,if the force acts on a particle whose position vector is $\vec{r} = 2\hat{i} + 2\hat{j} + 1\hat{k}$?

Why is the handle of a screwdriver made long to rotate a screw?

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

The torque of force $\vec F = -2\hat i + 2\hat j + 3\hat k$ acting on a point $\vec r = \hat i - 2\hat j + \hat k$ about the origin will be: