Free-Body diagram of the shaft A B C which cuts through A B shows the torques 600 Newton meter, 200 Newton meter acting on B and C, and a positive internal torque T subscript 1 acts on A B towards A. The length of A B is 100 millimeters, B C is 300 millimeters. The internal torque at A B is 400 Newton meter. A positive internal torque T subscript 2 acts on B C towards B. The internal torque at B C is negative 200 Newton meter. Tau at A B is 130.4 mega Pascal and Tau at B C is negative 65.2 mega Pascal.

To find the rotation angle at B, add the twist angle in shaft segment (1) to the rotation angle at A:

ϕB=ϕA+ϕ1

   =0+0.0158 rad   =0.0158 rad

To find the rotation angle at C, add the twist angle in shaft segment (2) to the rotation angle at B:

ϕC=ϕB+ϕ2

   =0.0158+(-0.0237)   =-0.0079 rad