A train slows down as it rounds a turn, going from $90\mathrm{.}0$ km$/$h to $50$ km$/$h in $15$ seconds. The radius of the turn is $150$ m$.$

Calculate the magnitude and the direction of the total acceleration of the train the instant the train reaches $50$ km$/$h$.$

Find the angular speed of the train at the instant the train reaches $50$ km$/$h$.$