28-Aug-2014 Free Fall Lab #2

This Lab is designed for students to figure out the value of g (gravity) through the measurement of a falling object on an apparatus.

 This apparatus has a falling distance of 1.5 meters. The way that the measurements are recorded is through a spark generator. As the object falls it will release a spark marking the paper that is hanging along the pole at approximately 1/60th of a second intervals on its way down.

 

With these marks we will have to measure the distance from the first dot to every other dot after. We measured for 23 dots after and plotted them on excel.

Once the distances were recorded for 1/60th of a second we had to find the distance (delta x) by subtracting the first distance from second, then the second from the third and so on. Then we find the mid interval time by grabbing the first time interval then adding 1/120 so that we can get the middle of each 1/60th second. As for the mid interval speed we grab the delta x and divide by the 1/60th of a second. Once that is finished we graph the mid interval with the mid interval speed.

By graphing the mid speed and mid times and inputting a trend line we are able to determine the acceleration in cm/s^2 by using the slope gathered Which turned out to be 9.40 m/s^2 when converted. After this we graph columns t(s) and distance in centimeters.

When graphing the distance and time column, instead of choosing a linear trend line (black line through points) we graphed a polynomial column. The way we find acceleration is to find the slope and multiple by 2.

Conclusion

Once finished with with our graphs we had to figure out the places in which can cause error in our data. Nothing is absolute when experimenting. Other factors can come into play like friction in the apparatus or the paper that it is stamping can cause a slowness in the dropping of the object. With the table above we are able to calculate the error that has occurred according to the whole class. Ours being #6.

Then there was the relative difference that was calculated by getting the experimental value (9.40m/s^2) and subtracting the accepted value (9.81m/s^2) and dividing it by the accepted value then multiplying this by 100 to get the percentage error. Our error being -4.18%.