Blood is flowing through an artery partially clogged by cholesterol. Because of the clog, the effective diameter of the artery is small enough that the viscosity of the blood cannot be neglected. A surgeon removes enough of the cholesterol to double the flow rate of the blood through the artery. Assuming the pressure gradient across the artery remains the same before and after surgery, what ’ s the ratio of the blood flow's speed after surgery to its flow speed before surgery? Answer in numerical form only
