A particle P P\,P moves in a straight line so that, at time t t\,t seconds, its acceleration a m s−2a \text{ m s}^{-2}a m s−2 is given by
a={4t−t20≤t≤327t2t>3 a = \begin{cases} 4t - t^2 & 0 \leq t \leq 3 \\ \frac{27}{t^2} & t > 3 \end{cases} a={4t−t2t2270≤t≤3t>3At t=0t = 0t=0, P P\,P is at rest. Find the speed of P P\,P when
t=3t = 3t=3
t=6t = 6t=6