At t 0, a particle moving along an x axis is at position x0 $20 m. The signs of the particles initial velocity v0 (at time t0) and constant acceleration a are, respectively, for four situations: (1) #, #; (2) #, $; (3) $, #; (4) $, $. In which situations will the particle (a) stop momentarily, (b) pass through the origin, and (c) never pass through the origin?