3. The coefficient of elasticity of each of the four springs of a wagon weighing 6.4 ∙ 104 kg is 4.81 ∙ 105 N / m. At what speed does the car begin to swing due to shocks at the joints of the rails, if the length of each rail is 12.8 m?

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)