An engine piston has a stroke of 9.0 cm (the full length of its path)…

Step 1. Amplitude. $A = \dfrac{9.0\ \text{cm}}{2} = 4.5\ \text{cm} = 0.045\ \text{m}$.

Step 2. Frequency. $f = \dfrac{3000}{60\ \text{s}} = 50\ \text{Hz}$, so $\omega = 2\pi \times 50\ \text{Hz} = 314\ \text{rad/s}$.

Step 3. Speed. $v_{max} = 314\ \text{rad/s} \times 0.045\ \text{m} = 14.1\ \text{m/s}$.

Step 4. Acceleration. $a_{max} = (314\ \text{rad/s})^2 \times 0.045\ \text{m} = 4.44 \times 10^{3}\ \text{m/s}^2$, about $4440\ \text{m/s}^2$.