A horse canters away from its trainer in a straight line, moving 120 m away in 15.0 s. It then turns abruptly and gallops halfway back in 4.8 s.

(a) Calculate its average speed.

m/s

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

m/s

Answer: a) Average speed = 18.37m/s

b) Average velocity = - 2.25m/s The horse moved away from the trainer

Explanation:

a) Average speed = Total distance/Total time

S=d/t

S = (d1 + d2) / t1 + t2

Given: d1=120m, d2=60m

t1=5 secs, t2 = 4.8secs

S = (120 + 60) / (5 + 4.8)

S = 180 / 9.8

S = 18.37m/s

b) Average velocity V = (Vi - Vf) / 2

Vi = d/t = > 120/5

Vi = 8m/s

Vf = d/t = > 60/4.8

Vf=12.5m/s

Average velocity V = (8 - 12.5) / 2

V = - - 4.5 / 2

V = - 2.25 m/s