### Home > CALC > Chapter Ch2 > Lesson 2.2.3 > Problem 2-81

2-81.

In the case of the helium balloon.

average velocity between *t* = 0 and *t* = 10:

Now find the average velocity between *t* = 0 and *t* = 5.

This is an example of a finite difference table.

Use the eTool below to explore this.

Click on the link below to view the full version of the eTool. Calc 2-81 HW eTool

In this story, finite differences (Δ*y*) represent the average velocity over consecutive one second intervals.

Is the height of the balloon increasing, decreasing or both? How do finite differences help you answer this?