Problem $3.$ For the two torsion members given below, determine the reacting torsion at A and draw the torsion,

$\frac{T}{J}G$ and rotation diagrams. Note the changing $J$ values along the member lengths. Shear modulus $G$ is

constant.

Problem $4.$ Draw the rotation diagram for the torsion member below. The circular solid section radius changes

from $2\mathrm{.}5$ in$.$ to $5in.$ from $B$ to $C,$ and the reverse from $C$ to $D.$ Determine maximum shear stresses along the

member length at $A,B,C,D$ and $E.$