A minivan starts from rest on the road whose constant radius of curvature is $40$ m and whose bank angle is $10.$ The motion occurs in a horizontal plane. If the constant forward acceleration of the minivan is $1\mathrm{.}8\frac{m}{s^2},$ determine the magnitude $a$ of its total acceleration $5$ seconds after starting.

Ans. $a=2\mathrm{.}71\frac{m}{s^2}$