## College Physics (4th Edition)

Let the east direction be the positive direction and let the west direction be the negative direction. $v_1 = 12~m/s$ $v_2 = -15~m/s$ We can find the change in velocity: $\Delta v = v_2-v_1 = -15~m/s-12~m/s = -27~m/s$ The change in velocity is 27 m/s in the west direction.