Answer
$3.2$ Hz
Work Step by Step
We know that frequency is:
$$f=\frac{1}{T}$$
We also know that the formula for period is:
$$T=2 \pi \sqrt{\frac{m}{k}}$$
Substituting the second formula in the first formula and substituting the values, we find the value of frequency:
$$f=\frac{1}{2 \pi}\sqrt{\frac{k}{m}}=\frac{1}{2 \pi}\sqrt{\frac{480}{1.2}}=3.2 Hz$$
