17. A distance-time graph indicates that an object moves 120 meters in 5 seconds and then remains at rest for 5 seconds. What is the average speed of the object?

12 m/s

Explanation:

Speed is distance moved per unit time and expressed as

S=d/t

S is speed, d is distance and t is time.

When at rest for five minutes, distance moved is zero hence speed is 0/5=0 m/s

When having moved 120 m for 5 s then speed is

S=120/5=24 m/s

Average speed is the average of these two speeda

Average speed = (24+0) : 2=24/2=12 m/s

Therefore, average speed is 12 m/s