1- a train travels 92 kilometers in 3 hours, and then 55 kilometers in 3 hours. what is its average speed? 2- what is the speed of a bobsled whose distance-time graph indicates that it traveled 125m in 27s? 3- suppose you increase your walking speed from 4 m/s to 15 m/s in a period of 3 s. what is your acceleration?

1. The average speed is the ratio of total distance to total time:

... speed = distance/time = (92 km +55 km)/(3 h +3h) = (147 km)/(6 h)

... = 24.5 km/h

2. speed = distance/time = (125 m)/(27 s) = 4 17/27 m/s

3. a = ∆v/∆t = (15 m/s -4 m/s)/(3 s) = 11/3 m/s²

c

explanation:

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day