Question

how do these agreement or organisations enhance free trade in South Africa​

Answer 1

There is duty-free trade between South Africa and the other four countries (Botswana, Lesotho, Namibia, and eSwatini) that comprise the Southern African Customs Union (SACU). The Southern African Development Community (SADC) Free Trade Agreement, as of 2012, allows duty-free trade among 12 of the 15 members.

Answer 2

Answer:

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact.