Variational Principles
Variational Principle in Statics

• minimizing internal energy
• internal energy of two springs in serial

• minimizing internal energy
• internal energy of simple pendulm

Variational Principle in Statics under Constraints

• minimizing internal energy (Cartesian)
• internal energy of simple pendulm (Cartesian)
• constraints

Variational Principle in Dynamics

• solve the equation of motion of simple pendulum
• equation of motion of simple pendulum
• external torque

• solve the equation of motion of damped pendulum
• equation of motion of damped pendulum
• external torque

Variational Principle in Dynamics under Constraints

• solve the equation of motion of simple pendulum (Cartesian)
• equation of motion of simple pendulum (Cartesian)

ODE solver

• van der Pol equation
• solve van der Pol equation (fixed time step)
• solve van der Pol equation (variable time step)
• phase plot