If it helps, here's some sense of scale.

A phone vibrates at around 150 Hz.

The cell phone vibrator motor generally comes in at 10 mm x 4 mm diameter, and the spinning end can be characterized as 2 halves of a cylinder, with one side having 4mm radius, and the other having 2mm radius.

If placed on a surface, the motion of the phone would be characterized as 3*sin(x), in mm.

The RMS of the phone would be the square root of the integral from 0 to 2 pi of the frequency times the square of 3*sin(x), which equals approximately 65.12 mm/s.

https://www.wolframalpha.com/input?i=square+root+of+%28integrate%28150*%283+sin%28x%29%29%5E2%29+from+0+to+2+pi%29