Question

# 4. Average and instantaneous velocity

Suppose a skateboard is rolling up a straight smooth slope. The

skateboard moves

more slowly as it rolls up the slope; it comes to a stop for a moment; and then it rolls

back down the slope. An observer measures the skateboard's coordinate x as a

function of time to be

x(t) = 15 m + (12 m/s)t − (1.2 m/s^2)t^2

where x is measured along the skateboard's path.

(a) Modify the example Google spreadsheet or Python program (on Canvas under

"Files") to plot the skateboard's coordinate vs. time over the time interval from

t = 0.0 s to t = 10.0 s. (You can check your work on a graphing calculator, but

you will need to practice using the other tools anyway for upcoming exercises.)

(b) Determine the skateboard's displacement between ti = 1.0 s and tf = 7.0 s, to 2

significant figures.

(c) Estimate the distance traveled between ti = 1.0 s and tf = 7.0 s, to 2 significant

figures.