As two trains move along a track, their conduetors suddenly notice that they arc headed toward cach other. Figure $2-31$ gives their velocities $v$ as functions of time $t$ as the conductors slow the trains. The figure's vertical scaling is set by $v_{1}=40.0 \mathrm{~m} / \mathrm{s} .$ The slowing pro- cesses begin when the trains are $200 \mathrm{~m}$ apart. What is their separation when both trains have stopped?