Application Of Derivatives

A particle is moving on a straight line. The distance \(\mathrm{S}\) travelled in time \(\mathrm{t}\) is given by \(\mathrm{S=a t^2+b t+6}\). If the particle comes to rest after 4 seconds at a distance of \(16 \mathrm{~m}\). from the starting point, then the acceleration of the particle is.