(4) The position vector r describes the path of a particle. Find the velocity, speed and acceler ation vectors of the particle. (a) r(t) : (t sint)i+(1 cos t)j (b) r(t) = 315i + 4cos tj 4 sin tk. (5) The acceleration of a particle moving in space is given by a(t) : 82ti4k. Find the position vector r(t) if v(0) = 31+ 4j 2k and r(0) = 2i + 2j k