A ball of mass m_b and volume V is lowered on a string into a fluid of density rho_f. Suppose that the object would sink to the bottom if it were not supported with the string.
* What is the tension T in the string when the ball is completely submerged but not touching the bottom, as shown in the figure?
Express your answer in terms of any or all of the given quantities and g, the magnitude of the acceleration due to gravity.