Motion Detector:

Acceleration of the ball as it hits the ground must be obtained. Thus, impact velocity and the time it takes for the ball to hit the ground must be recorded. Then, the following equation can be used to obtain acceleration:

The (velocity vs time) graph can also be used to obtain acceleration of the ball. All data obtained must be recorded in a table with the corresponding units.

Video Analysis:

Video Analysis is very useful, since one can view the data and video together. We also have to find acceleration of the ball using this method. In addition, it will provide you with position and velocity as well. After recording your data, the standard deviation (sd) must be obtained and the following equation can be used to obtain the desired measurements: At^2 + Bt + C

The (1st) derivative of the equation will give you velocity. And, the (2nd) derivative will give you acceleration.

Measurement Variability:

The following equation must be used to obtain percent difference:

There are a few errors that are present in both methods used. When using the motion detector, movement of hand of the person dropping the ball might get recorded. This may cause data to be altered. On the other hand, when using video analysis, it is important to have every frame at the center of the ball. At the very end, you have to estimate uncertainty by using the following 3 steps:

(1) Average of all measurements.

(2) Difference of each measurement from the average(deviation) using absolute value.

(3) Average of all deviations, divided by number of measurements.