Steven+and+Tosi

__**Bombs Away Lab**__
by Justin Tosi and Steven Thorwarth Period 2 Lab date: 9/27 Due date: 9/28


 * Purpose:** To find the acceleration of an object that is free falling caused by gravity. "freefall" and "caused by gravity" are redundant.


 * Hypothesis:** Using our knowledge of the relationship between position v. time graphs, velocity v. time graphs, and acceleration v. time graphs we can determine the average acceleration caused by gravity on a free falling object. We also hypothesize that our acceleration due to gravity should be close to 981 cm/s^2, as that number is the theoretical acceleration due to gravity.

1. Ticker Tape timer 2. Ticker tape 3. masking tape 4. mass 5. clamp 6. meterstick
 * Materials:**

1. Clamp the ticker tape timer to a high surface (i.e. the top of a cabinet) 2. Run a small amount of the ticker tape through the ticker tape timer without starting the ticker tape timer in order to attach the mass to the bottom of the ticker tape. 3. Use masking tape to attach the end of the ticker tape that has gone through the ticker tape timer to the mass. 4. Turn on the Ticker tape timer, making sure that the ticker tape timer is set to 60 Hrz. 5. Drop the mass, pulling the ticker tape through the ticker tape timer. 6. Remove the mass and tape the ticker tape to a desk in order to properly measure the distance of each dot from the beginning of the tape. 7. Measure the distance of each pair of dots from the beginning of the ticker tape. 8. Use these measurements to make a position v. time graph and calculate the acceleration of the mass falling because of gravity.
 * Procedure:**




 * Data:**sig figs should be the same for all values in a given column. And 7 is WAY too many.




 * Calculations:**

Calculations needed to find acceleration (a) y= Ax 2 + Bx, y= A(t) 2 + B(t) d= Vit +1/2at 2 A = a/2 548.45= a/2 __1096.9 cm/s^2=a__


 * Discussion Questions:**

1. Our graph agrees with the expected results and we know this because our R^2 results were .9995, which is very close to 100% similar to what was expected. Our graph was a polynomial graph and followed the guidelines Ax^2+Bx with 99% accuracy, so we are certain that our graph agrees with the expected graph.

2. Our calculations resulted in an acceleration caused by gravity equal to 1096.9 m/s^2 which is slightly greater than the class's average of 926.39 m/s^2. To see how our results compared with the results of other groups we calculated the percent error of out results to the class average. We took the absolute value of our results (1096.9 m/s^2) subtracted by the class average (926.39 m/s^2) and then divided by the class average. The result was 0.184 or 18.4% error

3. We can see that the object accelerated uniformly on the graph, because it is increasing exponentially. Between each point on the graph the position is increasing with larger intervals over a longer period of time.

4. The velocity v. time graph of this object should look like a straight line starting at zero with a constant positive slope.

5. The equation of the line for the v-t graph would be y=548.45x^2 + 22.966. not x^2

6. One reason why acceleration in our lab could have it higher than the theoretical value for gravity could be attributed to an incorrect procedure. For example, if I did not just drop the weight and the ticker tape, but instead pulled down on both of them, gravity and the action of me pulling down the weight would be measured, not just the acceleration due to gravity.

One reason why acceleration in this lab could have been lower than the theoretical value for gravity could be due to an incorrect procedure. If I let the ticker tape run through my fingers as the weight dropped to the floor, this would have slowed down the weight and the acceleration would not be very close to its theoretical value. After our calculations, we would actually be finding the experimental value for acceleration due to gravity and the negative acceleration due to my fingers slowing down the ticker tape. Another reason why acceleration could be lower than the theoretical value could be attributed to a piece of ticker tape that is too short. If our ticker tape was very short and only had 5 or 6 points recorded on it, we would not have collected enough data to see ticker tape and weight falling at complete free fall. As a result, our experimental value for acceleration would be a lot smaller than the theoretical acceleration due to gravity. Lastly, if the tape was too long and got caught on the top of the door where we hung our ticker tape timer, this would slow down the acceleration over that time period, eventually making the overall acceleration smaller.

In this lab, our results were not expected. Our experimental acceleration due to gravity was more than the theoretical acceleration due to gravity. I explored the different possible reasons for this when answering discussion question #6. Looking back, Steve and I should have run multiple trials to isolate the problem in my dropping technique so we could attempt to get more accurate results.Recap results here. Use numerical evidence.
 * Conclusion:**

As explained in the answer to #6 of the discussion questions, there are many ways that we could have tried to rectify our mistakes that caused our high 11.8% error. One of these corrections was to make sure that I focus on just simply dropping the weight and not inadvertently pulling it towards the floor, thereby making the experimental acceleration due to gravity much larger than the theoretical acceleration due to gravity. Since we were had a greater acceleration than the theoretical acceleration, we will not need to put as much focus on making sure we don't slow down the weight as it drops or make sure the tape does not get stuck on the top of the door, two mistakes that would yield a much smaller acceleration due to gravity.

The point of this lab was to try to prove the value of the acceleration due to gravity and as a class, we came relatively close to the theoretical acceleration due to gravity, 981 cm/s^2.