Cars A and B are racing each other along the same straight road in the following manner: Car A has a head start and is a distance DA D
A
beyond the starting line at t=0
t
=
0
. The starting line is at x=0
x
=
0
. Car A travels at a constant speed vA
v
A
. Car B starts at the starting line but has a better engine than Car A, and thus Car B travels at a constant speed vB
v
B
, which is greater than vA
v
A
.