Question

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 1

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