# acceleration due to gravity lab report

Topics: Error, Scientific method, Time Pages: 7 (978 words) Published: September 17, 2014
﻿
Acceleration of Gravity Using Smart Timers:
To calculate the acceleration of gravity using the Smart Timers

Steven Ge

AP Physics B1, Per. 7, JSerra Catholic High School

Sep 11, 2014

Abstract
The purpose of this lab is to calculate the acceleration of gravity using the Smart Timers. Drops of ball of equal size and start drops at one hundred centimeter height, the amount of time was counted used the Smart Timers. Repeat the same procedure ten times; the amount of times was counted used the Smart Timers.

After compared these data were compared, result is the data has about 0.01-second error. The most likely reason is the height is not constant, the each ball drops from approximately one hundred-centimeter height.

Theory
The height of a free falling object can be calculated using the following formula: Y = Y0 + V0t – 1/2 * gt­­­­­2, Note: Y – Y0 =the height. Using this formula, it will be up to solve for “g” and show that formula: g = 2(Y – Y0)/ t2. Follow the formula Y – Y0 =the height, so the Y – Y0 = 100cm. Then using the times data that got from the tests. The result of calculates, it got the several different “g”, take an average. Throw out an extremely large or small value.

Hypothesis
This lab was designed to calculate the acceleration of gravity using the Smart Timers. The theory predicts that g = 980cm/s2. In the class, the “g” most time is considered to be 9.8m/s2. Materials

Yellow plastic ball
The Smart Timers
Iron Bracket
Clamp
Photogate

The yellow plastic ball is as subjects. Iron Bracket use to constant the height, and clamp use to stable the Smart Timers attached on the Iron Bracket. The Smart Timers is use to count the amount of time. Target pad is part of the Smart Timers, it use to when ball fall on it, it will back to Smart Timers to make it stop timing. Photogate also the part of the Smart Timers, it use to back to Smart Timers the ball start drop, to make Smart Timers start timing.

Procedure
First check the height is 100cm; place the photogate with the bar and attached it to the lower clamp on the main bar-stand. Place the plug from the photogate to the #1 spot on the smart timer. Tightened the clamp so that it is perpendicular to the main bar stand. And make sure place the “pad” on the floor directly below the photogate, also do not step on the pad. Connect the plug from the pad to the spot on #2 spots on the smart timer. Then turn on the smart timers, now press #1 “button” to “time”. Now press the #2 button 3 times until it says “2 gates”.

After below the step, push the “3 Button” twice until a “star” shows up and take the “yellow” plastic ball and position it near the photogate. After pressing “3” start/stop button twice until a “star” appears on the screen, release the yellow plastic ball and measure the time it takes to fall. Do this 10 times and take an average. Throw out an extremely large or small value.

Data
The following chart details the ten times trials of the experiment and includes an average of the ten times trials. The average of the ten times trial; throw out an extremely large or small value.

Amount of times that yellow plastic fall on pad
Trial
Time (s)
g (cm/s2)
1
0.3708
1454.62
2
0.3797
1387.23
3
0.3685
1472.84
4
0.3697
1463.29
5
0.3714
1449.93
6
0.3723
1442.93
7
0.3656
1496.30
8
0.3744
1426.78
9
0.3807
1379.95
10
0.3617
1528.74
Average (throw out an extremely large or small value)
0.37155

1448.76

The final average value: g = 980 cm/s2.

Data Analysis
The data collected show the ten times amount of time that yellow plastic ball fall on pad, the all ball is drop from the same height. The data also show the average value of time and “g”. (Throw out an extremely large or small value)

The result have an anomalies, it’s much bigger than the prediction that g = 980cm/s2. It has a considerable error with...