The angular acceleration of the 600-mm-radius circular plate shown is defined by the relation \alpha={ \alpha }_{ 0 }{ e }^{ -1 }. Knowing that the plate is at rest when t = 0 and that { \alpha }_{ 0 }=10 \ rad/{ s }^{ 2 }, determine the magnitude of the total acceleration of Point B when (a) t = 0, (b) t = 0.5 s, (c) t =\infty.