Let the mass of 2500 kg car be
and it's velocity be
and the mass of 1500 kg car be
and it's velocity be
.
After the bumping the mass be M and it's velocity be V.
By law of conservation of momentum we have

2500 * 5 + 1500 * 1=4000 * V
V = 14000/4000 = 7/2 = 3.5 m/s
So the velocity of the two-car train = 3.5 m/s
Displacement = 0, assuming that he runs back to original position
Average velocity is displacement/ time, since displacement =0, velocity is also 0
Answer:
This passage is part of the resolution because it shows what happens after the climax. It wraps up the conflict, and then the story is over.
Explanation: cause I am smart thats why
' A ' is one crest of the wave. After every wavelength, there's another one.
' B ' . . . the vertical arrow under B shows the amplitude of the wave
' C ' is one trough of the wave. After every wavelength, there's another one.
' D ' . . . the horizontal arrow over D shows the wavelength.