b) The water tank shown in the Figure can be treated as a SDOF structure with the following properties: \( m=700,000 \mathrm{~kg}, k=7000 \) \( \mathrm{kN} / \mathrm{m} \). As a result of an explosion, the tank is subjected to the dynamic-load history shown in fig.
Compute approximately the maximum overturning moment MO (in N -mi) at the base of the tower:
Dynamic loading history