The blood flow speed through an aorta with a radius of 1 cm is 0.28 m/s. If
hardening of the arteries causes the aorta to be constricted to a radius of 0.8 cm, what is the new blood flow speed? I thought I knew how to do it.. just need to know the basic information to set it up.

Question

The blood flow speed through an aorta with a radius of 1 cm is 0.28 m/s.  If 
hardening of the arteries causes the aorta to be constricted to a radius of 0.8 cm, what is the new blood flow speed? I thought I knew how to do it.. just need to know the basic information to set it up.

jamesj · Answer

Ask yourself what volume of blood flows past a point in the aorta in one second in the first case.  This must be equal to the volume of blood pumped in the second case.

This will tell you how to find v for the second part.