Viscosity if liquid rhodium ball flows through
A researcher in Urumqi drops a rhodium ball of diameter 4.20 mm through a dilute aqueous solution of a high molar mass natural gum contained within a glass tube which has four graduations marked 10 cm apart. It is 18 C in the laboratory and the ball takes 1.86 seconds to fall between the first and second marks, 1.74 seconds to fall between the second and the third, and 1.74 seconds to fall between the third and the fourth.
What is the viscosity of the liquid?
What other information should be provided to allow you to answer the question more accurately?