a(t), v(t) & a(t) 1. A particle moves horizontally with its position (in rn) given by, 50:) = t3 9t2 + 24t, 05 s t s 63. Determine ; a) the velocity and acceleration functions. b) v(O) and a(O). c) the time(s) the particle changes direction. d) is the particle advancing or retreating at t = 53. e) the time interval(s) the particle speeding up