To measure the acceleration of free fall, "g."
We have said that if you drop an object from rest the distance the object falls, d, is related to the time, t, by:
where t is the time that it takes to fall the distance d. Solving for g gives:
Therefore, it is theoretically straightforward to determine the acceleration of free fall simply by dropping something and measuring the time it takes to hit the ground.
Experimentally, however, it is exceedingly difficult to get precise-enough times for meaningful results. (It often turns out that the theoretically straightforward approach is exceedingly impractical in the "real world.") Over short distances (and short times), human reaction time destroys the precision of the measurement, and over long distances, air resistance becomes a factor so that the acceleration of the object is no longer constant and the calculation is invalid. These considerations (among others) are what forced Galileo to develop his famous inclined plane experiment.
The Pasco Free-Fall Adapter gives us the technology to obtain precision timing for objects dropped relatively short distances, however. When the ball is dropped, it activates a switch to start a very accurate timer. When the ball strikes the pad at the end of its fall, it trips another switch to stop the timer. Simple and straightforward!
Pasco Science WorkshopTM interface |
free-fall adapter |
meter stick/metric tape |
metal sphere |
ring stand |
ring stand clamp |
C-clamp |
The apparatus will be set up for you.
The conclusions for this lab are on the data sheet.