Acceleration lab - lab report PDF

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Lab Exercise 2: Acceleration Abstract: The aim of this lab exercise was to determine the acceleration due to gravity of a Vernier picket fence. We will calculate the acceleration due to gravity of this object by measuring the height and the velocity, depending the height of the Vernier scale. First, we measured the length of the entire Vernier scale to calculated the length of each of the black and white segment. To calculate the length of each segment, we divided the total length of the scale by the total number of the segments which gave us the length of 4.99 cm/segment. The part 1 was to measure the g using the velocity vs. Time graph. The next step of this lab was to throw the Vernier scale through a photogate, for 5 times, which was attached to the lab pro system in the computer and gave the accurate time and speed of the Vernier fence. For each of these five trials, we calculated the run time of the Vernier fence which was given as the segments/s2 and then calculated the average of these five trials. The next step is to calculate the g in the units of cm/s2. In part 2, we calculate the acceleration due to gravity by dropping the Vernier fence from specific heights. The ratio of heights increases by 2 cm in each of the trials. We use the lab pro data collector for this experiment too as we did for the first part. The formula that we use in this experiment is the kinematic equation:

Data: Separate attachment. Plot:

Here we find out that the slope of our plot of v2 vs. h graph comes out to be 19.1 m/s^2. This shows that our slope is within the range to agree with the constant of acceleration due to gravity which is 9.81 m/s^2. Our slope agrees with the gravitational acceleration because our slope is the multiple of 2. so, by dividing the slope value by 2, we get it as 9.55 m/s^2 which is clearly within the range to agree within uncertainty. Analysis: In this lab, we tried to release the ruler from a stationary state. However, it may be the case that our hand was moving slightly. If we (consistently) gave the ruler a downwards initial velocity as we released it, the impact of this on our measurements is the amount of time it takes to pass through the photogate. The uncertainty of the experiment would much larger in this case. The experiments are not always perfectly precise, but if the movement in hand is consistent in every experiment, it would be hard finding an accurate velocity and the time taken to reach through the photogate.

D is the distance from the leading edge of the first black tape to the leading edge of the final black tape. If you measured the length from one corner to the opposite corner, you over estimate the length. Let's call the overestimated length D1. Now you drop the ruler straight, and measure the time it takes the ruler to pass through. Now we conclude that the ruler has travelled D1 length in time t, but in reality, it has only travelled D length in time t. So, we end up with a larger measured velocity D1/t and therefore a larger acceleration. We overestimate g if we do the experiment this way by getting a larger acceleration. In this part, we drop the ruler at an angle 'x' rotated about axis 4. So, the length of the ruler increases to D1=D/cos(x) from the actual length D. In the experiment you measure the time it takes the ruler to fall through the detection points. Because of the longer length, it takes longer time 't1' to fall through the detection points. But we initially measured the correct value of D. And we end up calculating velocity D/t1 which is smaller than it actually should be, and thus under estimate the value of g. When rotated by an angle 'x' about axis 5 and then dropped, the length which passes through the detector is D2=Dcos(x) is less than the actual length D. Therefore, we measure a smaller time t2. Then we calculate the velocity as D/t2 which is larger than what should actually be measured, we overestimate g just like we did n the answer no. 2 of the analysis. Finally rotating about axis 6, does not change the length that travels through the detector. And the time measured by the detector is accurate and we get the correct value of g....