17. The initial position and velocity of a projectile are given by r = 3i + 4 j and =67 +8 j respectively, and where r is in m and v in m/s. The position in the horizontal direction (in m) as a function of time is x(t) = 6t x(t) = 3+ 6t+ gt2 x(t) = 4 + 8t x(t) = 4+ 8t+ gt2