Abstract
Within this laboratory students used a Macintosh computer, scientificwork interface, and photogate to measure the acceleration of gravity, g, in a free-fall experiment. Using a “picket fence” dropped through a photo gate with disregard for air resistance; students calculated the results from the charted data and compared it with the accepted value of 9.8 m/s2 discussing any variations and their potential causes.
Goal
The goal of this experiment is to measure g, the acceleration of gravity, using various software and a picket fence.
Theory
Everything , regardless of mass, fall with the same acceleration due to gravity assuming that there is no air resistance. Items thrown upward or downward and those released from rest are falling freely once they are released. Any freely falling items experience an acceleration directed downward, regardless of the direction of its motion at any instant. Using the symbol g for this special acceleration, this value decreases with increasing elevation. At the Earth’s surface the value of g is approximately 9.8 m/sec2. Since students are disregarding air friction and assuming that the free fall acceleration does not vary with altitude over short vertical distances, the motion of a freely falling item is equivalent to motion in one dimension under constant acceleration. Therefore, the constant acceleration equations can be applied. For an item falling downward only under the influence of gravity can be graphically analyzed with a displacement versus time graph shown by a parabolic curve described in graph 1 below. This graph shows that as the item is falling, the displacement it travels each second is greater than the prior second. This graph can be mathematically illustrated by the equation which is the equation for displacement as a function of time.
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