posted by Melvin .
A car of mass m travelling at 20
m/s east on a straight level road and a truck of mass 2m travelling at 20 m/s west on the same road. What is the velocity of the car relative to the truck?
Vc = 20 m/s.
Vt = -20 m/s.
Vc-Vt = 20 - (-20) = 20 + 20 = 40 m/s.