Why are most organelles surrounded by membranes

Organelles are usually surrounded by membranes to keep them in one specific area, and they exist to make sure that a particular function can be carried out. They include things like the nucleus - the brain of the cell which sends out all the orders - or mitochondria , the 'power houses' of the cell, which produce energy in the form of ATP .

f=gm1m2/d^2 it d

f is force g is gravitaiton constant, m1 is mass of first object, m2 is mass of second object. d is distance between two object