Chapter 2 - Kinematics in One Dimension - Exercises and Problems - Page 59: 3

(a) first interval: $v_{ave} = -200~m/min$ second interval: $v_{ave} = 333~m/min$ (b) $v_{ave} = 120~m/min$

(a) first interval: $v_{ave} = \frac{\Delta~s}{\Delta ~t}$ $v_{ave} = \frac{-400~m}{2~min}$ $v_{ave} = -200~m/min$ second interval: $v_{ave} = \frac{\Delta~s}{\Delta ~t}$ $v_{ave} = \frac{1000~m}{3~min}$ $v_{ave} = 333~m/min$ (b) $v_{ave} = \frac{\Delta~s}{\Delta ~t}$ $v_{ave} = \frac{600~m}{5~min}$ $v_{ave} = 120~m/min$