The motion of an electron is given by \(x(t)=p t^{3}+q t^{2}+r\), with \(p=-2.0 \mathrm{~m} / \mathrm{s}^{3}, q=+1.0 \mathrm{~m} / \mathrm{s}^{2}\), and \(r=+9.0 \mathrm{~m}\). Determine its velocity at (a) \(t=0,\langle bangle t=1.0 \mathrm{~s}\), (c) \(t=2.0 \mathrm{~s}\), and \((d) t=3.0 \mathrm{~s}\).