If a rod or piece of wire is homogeneous, then its linear density is uniform and is

Question:

If a rod or piece of wire is homogeneous, then its linear density is uniform and is defined as the mass per unit length (ρ = m/l) and measured in kilograms per meter. Suppose, however, that the rod is not homogeneous but that its mass measured from its left end to a point x is m = f(x), as shown in Figure 5.

Figure 5

This part of the rod has mass f(x). X1 X2