When fluid in a long pipe starts up from rest at a uniform acceleration a$,$ the initial flow is laminar. The flow undergoes transition to turbulence at a time t$*$ which depends, to first approximation, only upon a$,$ $,$ and $.$ Experiments by P$.$ J$.$ Lefebvre, on water at $20$C starting from rest with $1-$g acceleration in a $3-$cm$-$diameter pipe, showed transition at t$*=1\mathrm{.}02$s $.$ Use these data to estimate $($a$)$ the transition time and $($b$)$ the transition Reynolds number Re D for water flow accelerating at $35$m$/$s$2$ in a $5-$cm$-$diameter pipe.