(1 point) Suppose Ht) : COS(7rt) i + Sin(7rt) j + 3th: represents the position of a particle on a helix, where z is the height of the particle. (a) What is 15 when the particle has height 15? t : 5 (b) What is the velocity of the particle when its height is 15? 1? : (c) When the particle has height 15, it leaves the helix and moves along the tangent line at the constant velocity found in part (b). Find a vector parametric equation for the position of the particle (in terms of the original parameter t) as it moves along this tangent line. L(t) :