Two cars crash at an intersection each going at a speed of $14\frac{(m)}{(s)}(31\mathrm{.}3mph)$ relative to the road. A small car $(1500kg)$ was travelling to the right while a larger truck $(3000$ kg $)$ was travelling leftwards.

a$.$ If the cars collide inelastically, what is the final velocity of the small car?

b$.$ What if the cars crashed elastically, what is the final velocity of the small car? $($Hint: this is more complex: momentum AND energy must be conserved, unlike in part a$.)$