18. A 2 kg block is sliding to the left across a friction-free surface at a speed of 6 m/s when it is struck by the force shown in the graph below. What Is the object's velocity (speed and direction) after the force Is done acting? F(N) 4000 t(msec) 19. Vector A has magnitude 14 units and points 60 degrees above the negative x axis. Vector B has magnitude 20 units and points straight to the right. What is the magnitude of Vector C = A + B? 20. Two boxes, A and B, are getting pushed across a frictionless surface by a person who pushes horizontally on the left side of Box A. The boxes are moving to the right and getting faster, Rank in order of magnitude (absolute value) the following forces. If there are any ties, indicate that clearly in your ranking: Next Force 1: person on Box A Force 2: Box B on Box A Force 3: Box B on person Force 4: Box A on box B Force 5: Box A on person