General equation of standing wave is

            y = (2A sin kx) constant ;

            V_p = –(2A ω sin kx) sin ωt ;

            a_p = –(2A ω² sin kx) constant ;

Force constant, $\mathrm{k}=\frac{\left(\mathrm{dm}\right)\left({\mathrm{a}}_{\mathrm{p}}\right)}{\mathrm{y}}=-\left(\mathrm{dm}\right){\mathrm{\omega }}^2$ is same for all elements except at nodes.

Velocity of particles on one half of wave will be in same phase and differ with the other half by π, but speed of all particles will be in same phase. Strain is maximum where potential energy is maximum which is possible at extreme position of each element that is maximum acceleration. The phase difference between two progressive waves is π so as to form standing wave.