Question
A disc rotates about its axis with a constant angular acceleration of $4\text{rad/s}^2$. Find the radial and tangential accelerations of a particle at a distance of 1cm from the axis at the end of the first second after the disc starts rotating.

Answer

$\text{t}=1\text{sec},\ \text{r}=1\text{cm}=0.01\text{m}$ $\alpha=4\text{rad/s}^2$ Therefore $\omega=\alpha\text{t}=4\text{rad/s}$ Therefore radial acceleration, $\text{A}_{\text{n}}=\omega^2\text{r}=0.16\text{m/s}^2=16\text{cm/s}^2$ Therefore tangential acceleration, $\text{a}_{\text{r}}=0.04\text{m/s}^2=4\text{cm/s}^2.$

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