To experimentally measure the downward acceleration solely due to gravity at the surface of the earth and with negligible air resistance on a free-falling object, a piece of clear plastic with evenly spaced black bars, labelled as a “picket fence,” was suspended from a string and dropped through a Photogate sensor. This software is used to measure the actual acceleration of gravity to compare it to the value provided by literature review. The Photogate sensor transmits an infrared beam of light to a detector across a gap. It then determines and records data when the beam of light is blocked by an object. The part of the picket fence that blocks the beam of light in this experiment is the black bars. As the picket fence falls through the sensor,
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Next, the picket fence was held up and dropped through the Photogate sensor, which would then send data to Logger Pro. Logger Pro simultaneously constructed a position-time graph, velocity-time graph, and an acceleration-time graph to represent the motion of the picket fence.
The upward-curved shape of the position-time graph suggests that the picket fence has a changing velocity. This curve signifies the object moving from slow to fast since the slope changes from small to big. On the other hand, the velocity-time graphs appeared linear and with a constant slope, so the “linear fit” function on Logger Pro was selected to fit a straight line to the data. Its shape was an increasing straight line, which signifies accelerated motion when an object is in free-fall. (See Fig. 1 and Fig. 2 below).
Figure 1: The Position-Time graph of the picket fence.
Figure 2: The Velocity-Time graph of the picket fence.
The slope of the velocity-time graphs was analyzed to determine whether or not acceleration was constant since all objects at the same location above the earth should have the same acceleration due to gravity. This process was repeated six times in order to establish the reliability of the slope measurements. (See Table 1 below).
Trial #
1
2
3
4
Next, the picket fence was held up and dropped through the Photogate sensor, which would then send data to Logger Pro. Logger Pro simultaneously constructed a position-time graph, velocity-time graph, and an acceleration-time graph to represent the motion of the picket fence.
The upward-curved shape of the position-time graph suggests that the picket fence has a changing velocity. This curve signifies the object moving from slow to fast since the slope changes from small to big. On the other hand, the velocity-time graphs appeared linear and with a constant slope, so the “linear fit” function on Logger Pro was selected to fit a straight line to the data. Its shape was an increasing straight line, which signifies accelerated motion when an object is in free-fall. (See Fig. 1 and Fig. 2 below).
Figure 1: The Position-Time graph of the picket fence.
Figure 2: The Velocity-Time graph of the picket fence.
The slope of the velocity-time graphs was analyzed to determine whether or not acceleration was constant since all objects at the same location above the earth should have the same acceleration due to gravity. This process was repeated six times in order to establish the reliability of the slope measurements. (See Table 1 below).
Trial #
1
2
3
4