Why Does My Handheld Shaker Shake at 159.2 Hz?

It all comes down to easy conversions. For a sinusoidal signal, vibration displacement, velocity and acceleration are related to each other by angular frequency as shown.

When frequency is 159.2 Hz, angular frequency is equal to 1000. Therefore, at 159.2 Hz, conversions from displacement to velocity and from velocity to acceleration can be accomplished by multiplying by 1000.

When shaking at 159.2 Hz, an object with acceleration of 9.81 m/s² has a velocity of 9.81 mm/s and a displacement of 9.81 microns.

There is a similar phenomenon at 61.4 Hz in English Units for velocity and acceleration only. At this frequency, 1 g of acceleration leads to a velocity of 1 in/s.

In the complicated world of vibration, easy math is good!