ITS FREE fall...

Purpose: The purpose of the lab is to find the constant of gravity by finding the change in distance in fixed time intervals of an object that is in free fall.

Equipment:

The apparatus in the picture is very simple. There is a weight that is on a wire that will drop from the top and go all the way to the bottom. There is a shocker that will send an electrical impulse to the falling weight every 60th of a second or .016666... seconds. A piece of paper will be between the falling weight and the source of the electrical impulse and a dot will be created at every point where the falling weight  was for each electrical impulse. In other words, the dots on the piece of paper measure the distance traveled by the weight for every 60th of a second.

Measuring the dots on the paper

Interpreting the data:

Data entered into Excel

The first column (position) in the Excel sheet is the distance (in centimeters) the first dot, which is assumed to be taken at the first electrical impulse or the first 60th of a second of the free fall of the object, is from the beginning of the piece of paper. The actual distance that was traveled isn't relevant but what is important is the change in position or delta x for each time interval. Having the change in position and the change in time gives the average velocity for that small interval. It is easy to see that there is a change in velocity when the values are placed one after another. A change in velocity in a fixed period of time gives us acceleration, however instead of creating a new column in the Excel program and writing a new equation to find the constant acceleration, making a graph of the velocity versus the mid time was easier and gives an average acceleration over the entire experiment. The mid time was used because it wouldn't make sense to say that there was a velocity at 0 seconds or when the object was at rest.

The equation displayed in the upper right hand corner of the is the y=mx+b version of the V(t)=gt+initailV. The only variable that is important of this particular graph is the constant g, which would be m in the equation displayed. The constant g determined is 974.8cm/s/s which is fairly close to the true value.





Conclusion:
There was only a single constant that was being determined and it was the experimental calue of g, 9.748m/s/s. When compared to the true value the percent error was -.53%, which means that there was minimal error. The most likely source of error for this was the fact that the falling weight was on a string, which could create possible tension that would prevent the weight from truly being in free fall.

Sincerely.

Swaggy C