Wednesday, October 1, 2014

3-Sep-2014: Determining the value of acceleration of gravity with a spark generator

The purpose of the lab conducted is to validate the value of the acceleration of gravity, -9.8 m/s^2, in the absences of all other forces such as air resistance.

The apparatus presented below is a column, measuring approximately 1.5 meters, which contains an electromagnet at the top that holds a mass connected to a spark generator and a strip of paper.


When the electromagnet is turned off the mass falls and the spark generator marks the strip of paper ever 1/60th of a second until the mass comes to rest. The result is a strip of paper marked with multiple dots varying in distance from one another as seen below along side the meter stick.


We then recorded the distances between each of the dots and their positions from the origin in order to find the change of distance through time assuming the first point we chose as time t. Once our data was recorded we proceeded to find the velocity of the mass at each time interval as well as the mid interval of time. The velocity as it traveled down the column was determined by dividing the distance it covered by 1/60th of a second.

Velocity = distance / (1/60 s.)

 The mid-interval was determined by adding a half of 1/60th of a second (1/120th of a second) to each point of time recorded by the spark generator. 

Mid-Interval = time + (1/120 s.)

This was all calculated with excel as seen below.


With this data we were able to construct a graph that depicted the relationship between the masses velocity and the mid-interval of time it corresponds to projecting a constant slope which would us the experimental value of the acceleration of gravity.



The slope recorded was approximately 9.94 m/s^2 only tenths off of the real value 9.8 m/s^2. All though the experimental value was not exact our results project that the value of gravitational acceleration is accurate. 

In conclusion it can be decided that the value of gravitational acceleration is indeed correct and it can be concluded that our experimental value is slightly off due to human error such as rounding numbers or mishaps in calculations. 

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