For a particle to be in equilibrium,what must be the net force acting on it?

$A$ book is lying on a table. What is the angle between the normal reaction acting on the book on the table and the weight of the book (in $^\circ$)?

Two equal heavy spheres,each of radius $r$,are in equilibrium within a smooth cup of radius $3r$. The ratio of the reaction between the cup and one sphere to that between the two spheres is:

$A$ $1 \text{ N}$ 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

$A$ rope of mass $5 \,kg$ is hanging between two supports as shown. The tension at the lowest point of the rope is close to ........... $N$ (take $g=10 \,m/s^2$).

Consider the following statements about the blocks shown in the diagram that are being pushed by a constant force $F$ on a frictionless table:
$A.$ All blocks move with the same acceleration.
$B.$ The net force on each block is the same.
Which of these statements is/are correct?