Linear Motion HELP!?

Question

A horse canters away from its trainer in a straight line, moving 150 m away in 12.0 s. It then turns abruptly and gallops halfway back in 5.4 s.

Calculate its average velocity for the entire trip, using "away from the trainer" as the positive direction.

Using sig figs as well, I was wrong with 13 and 12.9

help?

Answer 1

halfway is 75 meters.

Total distance is 150+75 = 225 m

total time is 12+5.4 s = 17.4 s

average speed is 225/17.4 = 12.9 m/s

Average velocity is different.

displacement is 75 meters (150-75)

time is 17.4s

average velocity is 75/17.4 = 4.31 m/s

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