A particle executes simple harmonic motion with amplitude $0.2$ m and period $\pi$ s. Find its maximum speed.

$\omega = \dfrac{2\pi}{T} = \dfrac{2\pi}{\pi} = 2$ rad s$^{-1}$, and maximum speed $v_{max} = \omega A = 2 \times 0.2 = 0.4$ m s$^{-1}$. Using $\omega = 2\pi$ by mistake gives about 1.26.