Which of the following sets of concurrent forces may be in equilibrium?

The following forces start acting on a particle at rest at the origin of the coordinate system simultaneously: ${\vec F_1} = -4\hat i - 5\hat j + 5\hat k$,${\vec F_2} = 5\hat i + 8\hat j + 6\hat k$,${\vec F_3} = -3\hat i + 4\hat j - 7\hat k$,and ${\vec F_4} = 2\hat i - 3\hat j - 2\hat k$. The particle will move:

Block $A$ of mass $4 \; kg$ is to be kept at rest against a smooth vertical wall by applying a force $F$ as shown in the figure. The force required is .......... $N$ $\left(g = 10 \; m/s^2\right)$. (in $\sqrt{2}$)

$A$ man is standing on a balance and his weight is measured. If he takes a step to the left side,then his weight:

There are four forces acting at a point $P$ produced by strings as shown in the figure. Point $P$ is at rest. The forces $F_1$ and $F_2$ are respectively:

$A$ body of mass $1 \ kg$ is suspended with the help of two strings making angles as shown in the figure. The magnitudes of tensions $T_1$ and $T_2$,respectively,are (in $N$):