Which expression represents the conversion of frequency fff from Hz\text{Hz}Hz to ms−1\text{ms}^{-1}ms−1?
f1000\frac{f}{1000}1000f
f⋅1000f \cdot 1000f⋅1000
f60\frac{f}{60}60f
fff is already in ms−1\text{ms}^{-1}ms−1