Let J_f be the moment of inertia of the flywheel, J_b be the moment of
inertia of the ball, omega_f be the angular velocity of the flywheel, and
omega_b be the angular velocity of the ball.
According the conservation of angular momentum, the flywheel reaches the following steady-state.
angular momenum before = angular momentum after
J_f omega_f + J_b omega_b = (J_f + J_b) omega
J_f omega_f + J_b (0) = (J_f + J_b) omega
J_f omega_f = (J_f + J_b) omega
omega = J_f / (J_f + J_b) omega_f
J_f / (J_f + J_b) = 0.92 from real shooter data (the lowest point in the
flywheel angular velocity drop provides the multiplier).