Partner: Bryan Andrews

September 20, 2012

Laboratory #2: Acceleration due to Gravity

Introduction: The purpose of this lab is to measure the acceleration due to gravity of a free falling object.

The experiment makes use of the Behr Free Fall apparatus, a dc source to power the electromagnet needed to hold up the falling object and a high voltage spark generator to mark the spark tape every 1/60 second. Also needed will be a meter stick, a graphing calculator and something to record all findings.

Once the paper has been obtained mark off 21dots on it. Label all the dots 0-20. Use a ruler to measure the distance from dot 0 to dot 2, from dot 1 to dot 3. The uncertainty in the measurement should be of the distance between +-0.20 cm. Since the dots are measured 2 dots wide, the interval timeis 2*1/60 or 1/30. The easiest way to do this is divide 30s^-1 with the interval. The average velocity over the interval from the first dot to the 3 dot is the instenatenous velocity of the 2 dot. Repeat this step for the rest of the data. In the calculator, make a velocity versus time in the y/x values and use linear regression on this data. Use this to find the % error between the acceleration value and the accepeted value. Next use Error propagation rules for multiplication by a constant to determine the uncertainty in the velocities. Make a hand made graph of all findings and draw best and worst fit lines. Compute the slope and y intercept in order to express acceleration due to gravity and its uncertainty. Measure total distance from dot 0 to each dot.

Conclusion

The measured values acted the way that we expected them to