The transfer function of a system is given by $$H\left( s \right) = {1 \over {{s^2}\left( {s - 2} \right)}}$$. The impulse response of the system is

A system with an input x(t) and an output y(t) is described by the relation: y(t) = t x(t). This system is

The transfer function of a zero - order - hold system is

The unit impulse response of a linear time invariant system is the unit step function u(t). For t>0, the response of the system to an excitation e^-at u(t), a>0 will be