Gravity Report

Finding the Acceleration of Gravity

23/2/11
Jake Murray

Abstract:

Introduction:
Gravity(g) is the force which pulls objects towards the Earth. Because this is an acceleration it can be found by calculating the time it takes for an object to travel a known distance. In this experiment time will be represented by t and distance will be represented as s.
An electromagnet is a magnet which only becomes polarised when electricity is flowing through it. Therefore by adding a current of electricity the device will become magnetic. An apparatus was used to record the falling time by starting a timer when the current was taken from the electromagnet and stopping the timer when the ball dropped breaks the circuit (two tin foil pieces gently touching). A diagram of the apparatus is in the appendices.
The purpose of this lab is to find the acceleration due to gravity at 3 different, measured lengths and to compare these values, noting discrepancies in the findings.
There were 3 questions given to answer at the start of this lab. The first was to compare the found value of gravity with 9.8 ± 0.1m/s2 and explain the difference in results. The second question asked what factors other than uncertainties were able to change the results. The final question asked what advantages or disadvantages would be gained from a higher falling distance.
Methods:
First the apparatus (as seen in the appendices) was set up and the distance was measured from the bottom of the ball to the circuit it would break when it fell through it. The power supply was taken from the electromagnet and the fall time was recorded. This procedure was then repeated three times to calculate the mean. The height of the drop was then adjusted twice more to find the mean values of gravity for each height.

Results:

Distance(m) | Drop 1 time(s) | Drop 2 time(s) | Drop 3 time(s) | Mean drop time (s) | Gravity(m/s2) |
0.777±0.0005 | 0.400±0.005 | 0.400±0.005 | 0.400±0.005 | 0.400±0.005 | |...