Discuss the meaning of the result for total energy in a whole mass spring system

hsut

1. The problem statement, all variables and given/known data
Had to work out the total energy in a mass spring system (Part d of question), which has been found to be:

(v^2*m/4)[sin^2(nt) + sin^2(3nt)]


The next part of the question (e) says to 'Discuss the meaning of your result to part (d) above'

And I have no idea what to write! It is worth nearly 10% of the whole assignment! Any help would be much appreciated.

Thanks

voko

Your expression for total energy depends on time periodically. This cannot be true. It must either monotonically decay with time (if friction/resistance is present), or be constant.