JEE Advanced Model Paper 15 with solutions for online practice

Two identical rods each of length 2 m and having same mass are connected from end to end by means of a spring of spring constant (3 + 2√2) N / m. The other two ends of the rods are riveted to ground at O and are on a smooth horizontal surface. These two rods are free to rotate about the rivet on the horizontal surface. When the spring is in natural length the angle between the two rods is 60°. From this position each rod is pulled away from each other by an angle of 15° and released. Then the force on the rivet when they come back to their initial position in Newton is