When is an object said to be in equilibrium?

$A$ man of mass $50 \,kg$ carries a bag of weight $40 \,N$ on his shoulder. The force with which the floor pushes up his feet will be ......... $N$.

$A$ mass of $5\, kg$ is suspended by a rope of length $2\, m$ from a ceiling. $A$ force of $50\, N$ in the horizontal direction is applied at the mid-point of the rope. The angle made by the rope with the vertical,in equilibrium is ........ $^o$

$A$ $1 \text{ N}$ pendulum bob is held at an angle $\theta$ from the vertical by a $2 \text{ N}$ horizontal force $F$ as shown in the figure. The tension in the string supporting the pendulum bob (in newton) is

$A$ $100 \ N$ weight is suspended in a corner of a room by two cords $A$ and $B$ as shown in the figure. The tension in the horizontal cord $A$ is ............ $N$.

Define mechanical advantage in a lever.