(1 point) A particle starts at the point P = (2, -7, 2) and moves along a straight line toward Q = (3, -4, 3) at a speed of 5 cm/sec. Let x, y, z be measured in centimeters and t be measured in seconds. (a) Find the particle's velocity vector. V ( t ) = (b) Find parametric equations for the particle's motion. x(t) = y(t) = z(t) =