  A ball supported by a spring is set on top of a plate which is sinusoidal
vibrated. The motion is limited to one dimension motion. It is assumed that the
spring is an ideal one with zero mass. The vibrating plate is considered much
heavier than the ball, so that the ball motion has no influence on the plate
motion. Plate vibration frequency is varied around the frequency of ball-spring
system. Resonance phenomenon is reported, which needs a phase match condition
to occur.
