$$\lambda = \frac{v}{f}$$
where:
* $\lambda$ is the wavelength in meters
* $v$ is the speed of sound in meters per second
* $f$ is the frequency in Hertz
Substituting the given values into the formula, we get:
$$\lambda = \frac{965 \text{ m/s}}{384 \text{ Hz}} = 2.51 \text{ m}$$
The distance the wave travel one complete vibration is 2 wavelengths . In this case
$$d= 2 \lambda= 2(2.51\text{ m}) = 5.02\text{ m}$$
Therefore, the tuning fork vibrates 384 times per second, each vibration travels a distance of 5.02 meters in helium gas.