t 1 =
S 1
V 1 =
200
1 S=200S ,
t 2 =
S 2
V 2 =
400
1.5 S=266S ,
t=t 1+t 2=200+266s=466s.
V=
S
t =
600
466 m/s=1.29m/s .
答:他上学走路的平均速度1.29m/s.
t 1 =
S 1
V 1 =
200
1 S=200S ,
t 2 =
S 2
V 2 =
400
1.5 S=266S ,
t=t 1+t 2=200+266s=466s.
V=
S
t =
600
466 m/s=1.29m/s .
答:他上学走路的平均速度1.29m/s.