A method and apparatus is disclosed herein for enhancing accuracy of jumping by incorporating interestingness estimates. A crash detection system including at least one crash detection sensor mounted on the breakaway unit and a crash detection controller stops the machine when vertical movement of the breakaway unit exceeds a threshold. The invitation input may comprise a recommendation to a second user to take an action regarding content to be delivered over a content delivery system. In embodiments, fine adjustments are made to the output signal level of the upstream amplifier by varying a bias current of the DAC. The series of forces will cause the rotating disks to self center.