Concepts at a Glance Both equilibrium and nonequilibrium problems can be solved with the aid of Newton's second law. For equilibrium situations,
such as the gymnast holding the “Iron Cross” position in the left photograph, the acceleration is zero (). For nonequilibrium situations, such as the freely falling gymnast in the right photograph, the acceleration is not zero
().
). For nonequilibrium situations, such as the freely falling gymnast in the right photograph, the acceleration is not zero
(
).