Question

Larry drives 20.0 km to the east from his house then 20.0 km west back to his house, takes 5.0 mins to find his wallet and leaves again. Larry is 40.0 km east of his house 60.0 mins after he left the first time.
A) what is his avg. velocity?

B) what is his avg. speed?

Answer 1

Larry's average speed is 
                                       (total distance) / (total time).

                      Speed = (80 km) / (60 min) = 80 km/hr .


Larry's average velocity is  
                                         (distance between start- and end- points),
                                  in the direction from the start-point to the end-point.

                       Velocity = (40 km east) / (60 min) = 40 km/hr east .