ABSTRACT

Consider an interval (x,x + Δx) in Figure 10.1. Points on the string move perpendicular to the x direction; thus the sum of the x components of the tension forces at points x and x +Δx equals zero. Because the tension forces are directed along tangent lines, we have

− T(x)cosα(x) + T(x + Δx)cosα(x + Δx) = 0.