A loudspeaker cone must vibrate with a period of 0.050 s and an amplitude of 1.5 mm.
A sensor measures the frequency of the cone and the total distance between its furthest forward and furthest backward positions. The table shows the sensor records for four different settings of the signal generator that drives the cone.
| sensor record | frequency in Hz\mathrm{Hz}Hz | total distance in mm\mathrm{mm}mm |
|---|---|---|
| P | 10 | 3.0 |
| Q | 20 | 3.0 |
| R | 20 | 0.75 |
| S | 40 | 0.75 |
Which sensor record shows the required motion?
record R
record S
record P
record Q