$17\mathrm{.}2.$ The lfast train; known as YHT $($high speed train$)$ that runs between Ankara and Eski$$ehir$,$ has a scheduled average speed of $198k\frac{m}{h}.$ Give the results in three significant figures.

a$)$ If the train goes around the curve at that speed and the acceleration experienced by the passencers is to be limited $0\mathrm{.}050$ g $,$ what is the smallest radius of curvature for the track that can be tolarated?

b$)$ If there is a curve of radius $1\mathrm{.}25$ km on the track, to what speed must the train be slowed to keep the acceleration below the limit$?$

c$)$ What total work is done on a $75\mathrm{.}0$ kg passenger between these two curves?