9. Olympic gold medalist Michael Johnson runs one time around the track - 400 meters - in 38 seconds. What is his displacement? What is his average velocity?

10. If an object is moving eastward and slowing down, then the direction of its velocity vector is .

a. eastward

b. westward

c. neither

d. not enough info to tell

11. If an object is moving eastward and slowing down, then the direction of its acceleration vector is .

a. eastward

b. westward

c. neither

d. not enough info to tell

12. Which one of the following quantities is NOT a vector?

a. 10 mi/hr, east

b. 10 mi/hr/sec, west

c. 35 m/s, north

d. 20 m/s

13. Which one of the following quantities is NOT a speed?

a. 10 mi/hr

b. 10 mi/hr/sec

c. 35 m/s

d. 20 m/s

14. Which one of the following statements is NOT true of a free-falling object? An object in a state of free fall .

a. falls with a constant speed of -10 m/s.

b. falls with an acceleration of -10 m/s/s.

c. falls under the sole influence of gravity.

d. falls with downward acceleration which has a constant magnitude.

15. The average speed of an object which moves 10 kilometers (km) in 30 minutes is .

a. 10 km/hr

b. 20 km/hr

c. 30 km/hr

d. more than 30 km/hr