Final answer:
The frequency of the vibration is 880 Hz, which means the tuning fork vibrates 880 times per second.
Step-by-step explanation:
The frequency of the vibration can be determined from the given function, v(t) = 0.7 sin(880πt). The function is in the form of a sine wave, where the coefficient before the sine function represents the amplitude of the wave. The coefficient inside the sine function represents the frequency of the wave. Therefore, the frequency of the vibration is 880 Hz, which means the tuning fork vibrates 880 times per second.