How to find this laplace transformation?

[kloong]

System: U(s) ---> H(s) ----> Y(s)

the transfer fuction is: H(s) = s^2 / ( (s+1)(s^2 + 2s + 2) )

how to find the lapalace transform Y(s) of the output when the input is a unit step function?then how about the output time response y(t) (without imaginary terms) when the input is a unit step fuction?

thanks.

 

[Cyosis]

You know that the transfer function is given by $H(s)=Y(s)/U(s)$. What is the Laplace transform of the unit step function?