Hobbies And Interests
Things You'll Need
Instructions
Measure the length of the air table and the diameter of the air hockey puck. For example, you might find the length of the table is 90 inches and the puck is 3 inches in diameter.
Place a set of wood blocks under the legs at one end of the table. Measure the height of each end of the table, and the distance between the places where you measured the heights. Calculate the angle of the table as the arctangent of the difference in the heights divided by the distance between the overall length. For example, if one end is 38 inches high and the other is 34 inches high and the overall length is 102 inches, then the angle is:
arctan((38 - 34)/102) = 2.2 degrees.
Hold the puck against the upper edge of the air hockey table. Release it and start the stopwatch at the same instant. Stop the stopwatch when the puck hits the opposite side of the table.
Calculate the acceleration. The distance travelled under constant acceleration is given by the expression: d = (1/2) a x t^2. Rearranging that equation, a= 2 x d / t^2. For example, the distance is the table length less the diameter of the puck as determined in Step 1: 87 inches. You might measure the time as 3.4 seconds, giving the acceleration as
a = 2 x 87 /(3.4^2) = 15.1 inches per second squared.
Calculate the acceleration of gravity. The measured acceleration is the acceleration of gravity times the sine of the angle. For the example, g = a / sin (angle) = 15.1 / sin (2.2 degrees) = 393 inches per second squared, which is 32.8 ft/sec^2.
Repeat the measurement a handful of times, say three to five times.
Place another set of wooden blocks under the legs, raising the table a bit more, and repeat the entire measurement from Steps 2 through 6.
Average all the measurements together to improve the overall accuracy of your measurement of the acceleration of gravity.