Answer to Question #80941 in Physics for Jake

Question

A car drives 3.0 km stretch of road at a constant rate of 45 km/hr to the west. Two people are observing this car's motion from different locations. You use a coordinate system with the origin at the beginning of the 3.0 km stretch and call west positive and east negative. Your friend (out walking her dog) uses a coordinate system with the reference point at the end of the 3.0 km stretch and calls east positive and west negative. If you and your friend were asked about the car's average velocity for its entire trip, would your answers be the same? *

Answer 1

1) The car's average velocity for its entire trip:
v=v e_21=v(1)=v=45 km/hr.
2) The car's average velocity for its entire trip:
v^'=v e_21^'=v(-1)=-v=-45 km/hr.
So, the answers will be different.