A motorway designer can assume that cars approaching a motorway enter a slip road with a velocity of 10 m s−1

A motorway designer can assume that cars approaching a motorway enter a slip road with a velocity of 10 m s−1 and reach a velocity of 30 m s−1 before joining the motorway. Calculate the minimum length for the slip road, assuming that vehicles have an acceleration of 4.0 m s−2.