15. [-/1 Points] DETAILS LARCALC11 12.2.056. Find r(t) for the given conditions. r"(t) = -8 cos(t)j - 7 sin(t)k, r'(0) = 7k, r(0) = 8j r(t) =16. [-l6 Points] DETAILS LARCALC11 123.004. The position vector r describes the path of an object moving in the xy-plane. Position Vector Point r(t) = ti + (t2 + 4)j (1, 3) (a) Find the velocity vector v(t), speed s(t), and acceleration vector a(t) of the object. v(t) = 5(f) = W a(t) = (b) Evaluate the velocity vector and acceleration vector of the object at the given point v(1) = a(1) = UH 17. [-/3 Points] DETAILS LARCALC11 12.3.022. MY NOTES Use the given acceleration function and initial conditions to find the velocity vector v(t), and position vector r(t). Then find the position at time t = 5. a(t) = 5i + 3k v(0) = 9j, r(0) = 0 V(t) r(t) = r(5) =