#1. A car moving at the rate of 65 miles per hour passes a truck
moving in the same direction at 38 miles per hour.
The speed of the car from the truck's frame of reference is
27 miles per hour.
#2. The X-43 is the fastest aircraft ever. It flew a distance of 3,961 km
from Los Angeles to New York at the speed of 11,265 km/h.
It took the X-43 (3,961 km) / (11,265 km/h) = 0.352 hour, or 21min 5.8sec
to fly that distance?
#3. A mail carrier walked six blocks to the north one block to the east ,
and then six blocks to the south.
After these three moves, the mail carrier's displacement is one block
to the East.