A variable-speed belt drive consists of the two pulleys, each of which is constructed of...

A variable-speed belt drive consists of the two pulleys, each of which is constructed of two cones which turn as a unit but are capable of being drawn together or separated so as to change the effective radius of the pulley. If the angular velocity ω₁ of pulley 1 is constant, determine the expression for the angular acceleration of pulley 2 in terms of the rates of change of the effective radii.