The hollow shaft develops a higher maximum

shear stress than the solid shaft, because removing material from the centre

reduces J.

The

hollow shaft develops a lower maximum shear stress than the solid shaft,

because removing material reduces the cross-sectional area and therefore the

stress.

Both

shafts develop the same maximum shear stress because the outer radius is the

same.

The

solid shaft develops a higher maximum shear stress than the hollow shaft,

because its greater J means the stress is more spread out.