The acceleration of a test carriage on a straight track is modelled by a=(3t+5) m s−2a=(3t+5)\text{ m s}^{-2}a=(3t+5) m s−2 for t≥0t\geq0t≥0. When t=0t=0t=0, its velocity is 2 m s-1. When t=Tt=Tt=T, its velocity is 20 m s-1.
Find TTT. Give your answer to 3 significant figures.