.
3.0 m/s
5.0 m/s
50 m/s
60 m/s
Both runners are moving at the same speed.
Runner 1 has zero acceleration.
Runner 1 is overtaking runner 2.
Runner 2 is slowing down.
Constant acceleration of stone
Increasing acceleration of stone
Constant speed of stone
Increasing speed of stone
A
B
C
D
X
X +Y
Y
Y-X
A
B
C
D
40km/h
50km/h
60km/h
120km/h
10km/hr
20km/hr
30km/hr
60km/hr