Hi everyone. This question is giving me a real headache (literally). It should be simple, but I’ve spend probably the last 4-5 hours trying to figure it out. The left side of my brain is redundant. 1. The problem statement, all variables and given/known data The following specifications are used for the design of a flanged coupling between two coaxial shafts: Speed: 650rpm Power transmitted: 550 kW Bolt diameter: 12mm Pitch-circle diameter: 200mm Material: Mild steel Factor of safety: 4 Determine the number of bolts required, assuming the bolts are equally loaded. 2. Relevant equations Ultimate Shear Strength of mild steel = 360 N/mm^2 Shear stress (MPa) = Force (Newtons) / Area (mm^2) Factor of safety = Ultimate Shear Strength / Shear Stress 3. The attempt at a solution I cannot get anything down at all. And I also cannot understand why they have given me Speed and Power. Is there maybe some way to work out the force for the shear stress equation? Also for your information, this is question 27.11 from Val Ivanoff’s Engineering Mechanics. Any help would be much appreciated!