From Lecture Online

Demonstration of sinusoidal displacement curve for a SHM spring system.

Link – http://lectureonline.cl.msu.edu/~mmp/kap13/cd361a.htm

From Walter Fendt

Simple applet showing the mechanical resonance of a mass and spring. You can change the driver frequency.

Link – http://www.walter-fendt.de/ph14e/resonance.htm