Answer
$A$ is the amplitude of motion, $B$ is the angular frequency of motion, the frequency is $\frac{B}{2\pi}$.
Work Step by Step
The constant $A$ is in units of meters. This is the amplitude of motion. The constant $B$ is the angular frequency $\omega$, defined in terms of radians per second $(rad/s)$. Note that the frequency of motion can be related with angular frequency using the formula $$f=\frac{\omega}{2\pi}$$ Therefore, if $B=\omega$, the frequency must be $\frac{B}{2\pi}$.
