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

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )