Answer
(a) first interval:
$v_{ave} = -200 ~m/min$
second interval:
$v_{ave} = 333 ~m/min$
(b) $v_{ave} = 120 ~m/min$
Work Step by Step
(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) $v_{ave}=\frac{\Delta ~s}{\Delta ~t}$
$v_{ave} = \frac{600 ~m}{5~min}$
$v_{ave} = 120 ~m/min$
