How to find the cutoff frequency using Simulink (from the scope)?
Measure the time constant, \$\tau\$, of one of the exponentials (63% response time), and the cut-off frequency is the inverse of this, in rad/sec.

The scope's time and vertical scales need minor gridlines, but it looks like \$\tau\approx 10^{-4} \: sec; \:\therefore \omega_c\approx\large \frac{1}{10^{-4}}\small=10^4 rad/sec; \: f_c =1591 Hz\$