When is an object said to be in equilibrium?

Explain the main types of forces with suitable examples.

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

As shown in the figure,a $70\,kg$ garden roller is pushed with a force of $\overrightarrow{F} = 200\,N$ at an angle of $30^{\circ}$ with the horizontal. The normal reaction on the roller is $.......\,N$ (Given $g = 10\,m s^{-2}$)

The adjoining figure shows a force of $40\, N$ acting at $30^o$ to the horizontal on a body of mass $5\, kg$ resting on a smooth horizontal surface. Assuming that the acceleration due to gravity is $10\, ms^{-2}$,which of the following statements is (are) correct?
$[1]$ The horizontal component of the applied force is $20\sqrt{3}\, N$.
$[2]$ The weight of the $5\, kg$ mass acts vertically downwards.
$[3]$ The net vertical force acting on the body is $30\, N$ (upwards).

Two like parallel forces $20 \,N$ and $30 \,N$ act at the ends $A$ and $B$ of a rod $1.5 \,m$ long. The resultant of the forces will act at the point ........