## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

(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) $v_{ave}=\frac{\Delta ~s}{\Delta ~t}$ $v_{ave} = \frac{600 ~m}{5~min}$ $v_{ave} = 120 ~m/min$