Let's assume that in this case we have a mass hanging from a string and the system is in equilibrium. In an ideal case we can neglect the mass of the string and its elastic properties. In these conditions, the tension is constant and equal to the weight exerted by the body. It is then enough to use a dynamometer (it is not necessary to know the mass of the load) to measure the weight of the load and we will have the tension exerted by the string. In a more realistic model it is necessary to take into account the mass and elastic properties of the string. This produces that the tension is not constant and varies depending on the point of the string where it is measured. In this case the tension at the end of the string where the load is located is greater than in the ideal case.