Answer
$$a_{t}=-0.99 \mathrm{\ mm} / \mathrm{s}^{2}$$
Work Step by Step
With $r=500 \mathrm{mm},$ the tangential acceleration is
$$
a_{t}=\alpha r=-1.14 \mathrm{rev} / \min ^{2}\left[\frac{2 \pi \mathrm{rad}}{1 \mathrm{rev}} ]\left [\frac{1}{60 \mathrm{s}}\right]^{2}(500 \mathrm{mm})\right.
$$
which yields $a_{t}=-0.99 \mathrm{\ mm} / \mathrm{s}^{2}$
