When set on a rigid foundation and operating at \(800 \mathrm{rpm}\), a 200-kg machine tool provides a harmonic force with a magnitude of \(18,000 \mathrm{~N}\) to the foundation. An engineer has determined that the maximum magnitude of a harmonic force to which the foundation should be subjected to is \(2600 \mathrm{~N}\).

(a) What is the maximum stiffness of an undamped isolator that provides sufficient isolation between the tool and the foundation?

(b) What is the maximum stiffness of an isolator with a damping ratio of 0.11 ?