(iii) a) An infinite string lies along the x-axis. At time t = 0 it is hit with a single hammer blow, which strikes the string at all points along the interval [8, 10]. At what time will the subsequent vibration reach the point x = 25, if the movement of the string is governed by the wave equation utt Urz? b) What can be said about the long-term position of the string at a = 25? Carefully justify your answer.

(iii) a) An infinite string lies along the x-axis. At time t = 0 it is hit with a single hammer blow, which strikes the string at all points along the interval [8, 10]. At what time will the subsequent vibration reach the point x = 25, if the movement of the string is governed by the wave equation utt Urz? b) What can be said about the long-term position of the string at a = 25? Carefully justify your answer.