A slender 10-kg bar AB of length l = 0.6 m is connected to two collars of negligible weight. Collar A is attached to a spring of constant k = 1.5kN/m and can slide on a horizontal rod, while collar B can slide freely on a vertical rod. Knowing that the system is in equilibrium when bar AB is vertical and that collar A is given a small displacement and released, determine the period of the resultingvibrations.
Quantum solid in a quantum solid the dominant repulsive energy is the zero-point energy of the atoms. Consider a crude one-dimensional model of crystalline He4 with each he atom confined to a line segment of length L. In the ground state the wave function within each segment is taken as a half wavelength of a free particle. Find the zero point kinetic energy per particle.