Work this out? A rolling ball?

Question

A rolling ball moves from x1 = -2.0s to x2 = -4.2cm during the time from t1 = 3.0s to t2 = 6.1s. What is its average velocity?

Answer 1

Assuming x1=-2.0cm

change in distance = (-4.2-(-2)) = -2.2 cm

change in time = 6.1-3=3.1 seconds

Average velocity=change in distance /change in time

                       = -2.2/3.1 = -0.71 cm/s

Your moving along the negative x-axis.

Note: velocity is a vector "speed with direction"

Answer 2

(-4.2-(-2.2))/(6.1-3.0)

average velocity is essentially its change in displacement over the recorded time. so, total distance over total time.