# Chapter 2 - Describing Motion: Kinematics in One Dimension - Problems: 9

a. 3.68 m/s. b. 0 m/s.

#### Work Step by Step

a. The definition of average speed is the total distance over the time. The distance traveled is 8(400 m) = 3200 m. The time is (14.5 min)(60 s/min) = 870 s. $$\frac{3200 m}{870 s} = 3.68 m/s$$ b. The displacement is 0 m. $$\frac{0 m}{870 s} = 0 m/s$$

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