(a) Derive an equation for the radial acceleration that includes $v$ and $\omega,$ but not $r .$ (b) You are designing a merry-go-roundfor which a point on the rim will have a radial acceleration of 0.500 $\mathrm{m} / \mathrm{s}^{2}$ when the tangential velocity of that point has magnitude 2.00 $\mathrm{m} / \mathrm{s} .$ What angular velocity is required to achieve these values?