A ceiling fan has kinetic Momentum in 1 blade hitting a fixed target. Would the design allow the other blades to flex , reducing target impact? If the 4 blades are combined and bolted together at same velocity is different Momentum delivered? Similar q : a human arm is about 8kg and a sword about 1 kg. Does the hand-grip cause less impact than if the sword is welded into a steel-pin locked onto arm-bones? ( I'm guessing the answer is 50% maybe and it's not Physics..) ( but photos of skull damage and Newton calcs. suggest "yes" ).