Two carts A and B are moving in a straight line with velocities v and 2v respectively. The length of each of the carts is L. Cart A fires a projectile with an initial velocity u relative to cart A at initial angle ? (measured from the horizontal). What are the minimum and maximum values of u with which the projectile can be fired such that it hits cart B. The initial distance between the two carts when the projectile is fired is s. [5 points].