$\mathrm{}\mathrm{}$ Two carts connected with a compressed spring are placed somewhere along a frictionless track of $4\mathrm{.}0$ m in length. One cart has a mass of $150$ g$,$ and the heavier cart has a mass of $275$ g$.$ The spring is released, and the two carts move off toward the two ends of the track, reaching the ends at the same instant. 

 

a$.$ Which cart is initially closer to its end of the track, the light cart or the heavy cart?

b$.$ If the heavy cart gains a velocity of $2\mathrm{.}0$ m$/$s$,$ what is the velocity of the light cart?

c$.$ How far from its end of the track is the heavy cart placed initially?

d$.$ How much momentum is produced by the release of the spring?

e$.$ How much kinetic energy is produced by the release of the spring?

f$.$ Energy is always conserved. Where does the kinetic energy of the carts come from?

g$.$ If the compression of the spring is increased, which of these answers a$$f will change?