(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.

Parts D, and E

A 2-stage rocket is fired from rest. Its acceleration data are shown in the graph below. Plot the v-t and s-t graphs describing the motion of the rocket-clearly showing the shape of the curve (or add a note) and values at inflection points. Show any calculations as well. Then find the velocity of the rocket and its elevation after 20 seconds of flight. a (m/s?) 25 18 (s) 15 20

D, E, F

please help me solve part2

Q12 only