- #1

#### jfnn

## Homework Statement

Hi, I have a quick question about an experiment I am doing.

I did an experiment where I rolled a ball over a flat surface and dropped a ball from a height, and I was asked if the ball rolling over the flat surface (1-d) motion is subject to constant velocity? I was also asked if the ball dropped from a height is subject to constant acceleration? Here is my picture attached too. Both of the graphs are position vs. time. The parabolic graph is the graph where I have to know if the ball is subject to constant acceleration. The linear graph is the one that asks if it is constant velocity.

## Homework Equations

[/B]

I know if an object is at constant velocity, the position vs. time graph will be linear. This graph, the best fit line is linear; however, the velocity between individual points is not the exact same as the velocity of the best fit line (got this from slope), thus I said the velocity deviates and is not always constant due to forces, such as wind in my home or friction.

For the acceleratinon position vs time graph, I see that it is parabolic, which means that it should be constant acceleration. However, when I compare the quadratic equation for the line of best fit to the kinematic quadratic equation for position, i get different values of the acceleration. For example, the acceleration is not -9.8? It is -8.6...

Please help. Thank you.

## The Attempt at a Solution

Above. [/B]