During a marathon race, a runner's blood flow increases to 10.0 times her resting rate. her blood's viscosity has dropped to 85.0% of its normal value, and the blood pressure difference across the circulatory system has increased by 50.0%. by what factor has the average radii of her blood vessels increased?

1.543

Explanation:

According to Poiseuille's law, blood flow (Q) is given by:

Where ΔP is  the blood pressure difference, μ is the blood viscosity, r is the radius of the blood vessel, and L is the length of the vessel.

During a marathon, the new radii of her blood vessels (r') are

The average radii of her blood vessels increased by a factor of 1.543

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.