(1 point) Suppose r⃗ (t)=cos(πt)i+sin(πt)j+5tkr→(t)=cos( πt)i+sin(πt)j+5tk represents the position of a particle on a helix, where zz is the height of the particle. (a) What is tt when the particle has height 2525? t=t= (b) What is the velocity of the particle when its height is 2525? v⃗ =v→= (c) When the particle has height 2525, 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 tt) as it moves along this tangent line. L(t)=L(t)=