Diagram shows two shafts marked 1 and 2 of length 36 inches and 96 inches respectively. They are connected by two gears at B which has 24 teeth on the shaft 1 and at C which has 72 teeth on the shaft 2. The shaft 1 is connected to a motor at A. The shaft 2 has a gear at D on which a torque T subscript D is applied.

The angles of twist in shafts (1) and (2) are computed as follows:

ϕ1=T1L1J1G1   =(-43.768 lb-ft)(36 in.)(12 in./ft)(0.031063 in.4)(12,000,000 psi)   =-0.050724 rad

ϕ2=T2L2J2G2   =(131.303 lb-ft)(96 in.)(12 in./ft)(0.239684 in.4)(12,000,000 psi)   =-0.052590 rad