1/29/13
The purpose of this lab today is to determine the acceleration of gravity for freely falling object using the computer as a data collector.
Equipment: windows based computer, Lab Pro interface, Logger Pro software, motion detector, rubber ball, wire basket.
We used the computer to collect some position(x) vs time(t) data for a rubber ball tossed into the air. Since the velocity of an object is equal to the slope of the x vs t curve, the computer can also construct the graph of v vs t by calculating the slope of x vs t at each point in time. We used both the x vs t graph and the v vs t graph to find the free fall acceleration of the ball.
It was little hard to get a nice parabola graph by tossing the ball. we did several times to get a nice shape of parable.
Here is one of the result of our group.
Results from falling body experiment
trial 1: gravity exp(2a) is 9.92m/s^2 and 1.22% difference(percentage error)
gravity exp(m) is -9.98 m/s^ and 1.83% difference (percentage error)
trial 2: gravity exp(2a) is 9.85 m/s^2 and 0.51%% difference(percentage error)
gravity exp(m) is -9.89 m/s^ and 0.90% difference(percentage error)
trial 3: gravity exp(2a) is 9.8 m/s^2 and 0%% difference(percentage error)
gravity exp(m) is -9.8 m/s^ and 0% difference(percentage error)
Why does the curve have a negative slope?
The shape of the line on the graph (horizontal, sloped, steeply sloped, mildly sloped, etc.) is described for the object's motion.
This experiment, initial position starts increasing from positive, and turning to decrease passing by origin to negative.
Slope is to describe the steepness of a line. therefor, Slope line starts from positive to downward to negative. When you see the graph of the parabola, one half the parabola the slopes are all positive velocity and the other half of the parabola, the slopes are all negative velocity. Also, the slope of local maximum is horizontal which slope is 0. If slope is constantly decreasing or increasing, then acceleration is 0.
as closer to acceleration of gravity(9.8 m/s^2), percentage of error is lower.
Acceleration is second derivative which is the rate at which an object changes its velocity.
This is what I did in the lab.
