**P. 3937.** Two wagons of masses *m*_{1} and *m*_{2} are moving towards each other along a horizontal path. Their speeds are *v*_{1} and *v*_{2} respectively. *a*) What is their common velocity after they are hitched? *b*) What is the maximum compression of each buffer if the spring constant of all the four buffers are the same *D*? *c*) If the sum of the masses of the two wagons is constant at what ratio of the masses will the maximum compression be the greatest?

(5 points)

**Deadline expired on 11 January 2007.**