1. A high school athlete runs 100 m in 12.20 sec. What is her speed in m/s and in km/h? Ans: 8.2 m/s; 29.51 km/h
2. A bullet is shot from a rifle at 720 m/s. What time is required for the bullet to strike a target that is 3240 m,E? What is the velocity of the bullet in km/h? Ans: 4.5 sec; 2592 km/h, E
3. Light from the sun reaches the earth in 8.3 min. The speed of light is 3 x 10⁸ m/s. How far is the sun from the earth in meters? In kilometers? Ans: 1.49 x 10¹¹m; 1.49 x 10⁸km
4. On a baseball diamond, the distance from home plate to the pitcher's mound is 18.5 m. If a pitcher is capable of throwing a ball at 38.5 m/s, how much time does it take a thrown ball to reach home plate? Ans: 0.48 sec
5. A motorboat heads due east at 16 m/s across a river that flows due south at 9 m/s. The river is 136 m wide. How long does it take for the boat to reach the opposite side of the river? How far south of a point even with its starting point does it land? Ans: 8.5 sec; 76.5 m
6. A car travels 50 m at a rate of 10 m/s, S. It then travels 200 m at a rate of 20 m/s, N. What is its average speed? Its average velocity? Ans: 16.67 m/s; 10 m/s, N
7. Answer the following questions about the graph:
   • What is the speed between 10 and 15 sec? Ans: 2 m/s
   • How far does the object travel between 5 and 10 sec: Ans: 10 m
   • What distance does the object travel between 15 and 20 sec? Ans: 0 m
   • What is the object's displacement during this time? (You give the direction!) Ans: 30 m
   • During which time interval is the speed zero? Ans: 15 to 30 sec
   • Is there any acceleration (answer based upon what you have learned about the appearance of the graph)? Ans: no
   • When is the object's speed the greatest? Ans: 30 to 35 sec
   • What is this speed? Ans: -6 m/s

     

Velocity Notes

Velocity Sample Problems