Exercise 1 (10 points):
We consider the mechanical oscillatory system of the Figure 1. The rigid \( \operatorname{rod} \mathrm{AB} \) is of length \( 2 \ell(\mathrm{OA}=\mathrm{OB}=\ell) \) and a negligible rrass. It carries to its extremates the punctual masses \( m \) and \( M \). The two identical springs are welded at a point \( O \) ' to the \( \operatorname{rod}\left(\mathrm{OO}^{\prime}=\mathrm{a}\right) \). At rest \( (\theta=0) \), the rod is vertical and the springs are not deformed. The rod is turned through an angle \( \theta \) (small oscillations) around the rotation axis \( O \).
1) Determine the kinetic and potential energies of the system as a function of \( \theta \).
2) Used the Lagrange method to establish the differential equation of the motion.
3) Find the solution \( \theta(t) \).
Figure 1
4) For \( m=M \) and \( a=\ell / 2 \), deduce the period ( \( T \) ) of the oscillations.