Objective of Safety Nets:-

An object of safety net can be covered and protection of high risk factor of peoples in terms doing work in the construction, building, manufacturing and industries. The purpose of uses of the safety net is for maintained the low risk by giving accurate guidance and awareness to the peoples that how we can be reduced the minimum risk from it. 
Fall arrest safety nets or personnel safety netting is recognized by the UK Health & Safety Executive as their “preferred method of fall arrest when working at height”. 
A safety net is a net to protect people from injury after falling from heights by limiting the distance they fall, and deflecting to dissipate the impact energy. The term also refers to devices for arresting falling or flying objects for the safety of people beyond or below the net.

A net placed to catch an acrobat or similar performer in case of a fall. a safeguard against possible hardship or adversity. In physical terms resulting in a softer landing and much lower risk of damage.
There is role of materials, used to make the ropes of net (such as an iron rod grid will not work as good as flexible and extensible ropes), and the tension or stretch used to make the net (stored in the ropes), also have some roles. The net is to be set at an appropriate height from the hard ground, so that the object, along with the rope, does not clash with the hard ground.