Prediction 2: In order to make sure you are studying the effect of only one para
ID: 1776451 • Letter: P
Question
Prediction 2: In order to make sure you are studying the effect of only one parameter at a time (in our case the mass of the pendulum) how would you set up your experiment? What are the things that you think will need to be similar for both set-ups? Are those constraints achievable in the set-up present on your table?
In this activity you will measure the period of a simple pendulum.The materials you will need are: » photogate timer » step stool e large support stands . thread (string) » pendulum string clamp » brass and aluminum pendulum bobs » meter stick You are given a task of building a very simple, affordable and robust clock for an outdoor field work. You decided to hang a bob on a string and count number of full swings bob makes during an observation. You are tasked with finding out the time for one full swing (a.k.a. period) and converting the swings into seconds. You need to establish correct relation between the parameters of your pendulum in the lab first, so that you can reliably use your simple clock whenever vour research takes vou Naturally, you would like your clock to be as light as possible so the first thing you decided to check is if the time of a swing depends on the mass of the bob. You settled on a light aluminum bob, but you are worried that light material might not work as well as a sturdier but heavier bras:s bobExplanation / Answer
The simple pendulum consists of a small bob (weight) B on the end of a string secured on a rigid support F (the fulcrum). The bob is pulled aside a distance x and then released, allowing it to swing in a an arc. The time the bob takes for one complete swing is called its period.
Though many books give equations for the period of a simple pendulum, we will pretend that we don't know the equation, and try to "discover" it through experimentation.
The pendulum's period is is the time it takes to swing from one side to the other and return to its starting point. This may be easily determined with a stop-clock by counting a number of complete swings, say n, and dividing the total time by n.
We suspect the period could depend on at least the following factors: (1) mass of the pendulum bob, (2) shape of the bob, (3) volume of the bob, (4) length of the suspension string, (5) air resistance (drag) on the bob and string, (6) size of the swing (amplitude), (7) Size of the gravitational force.
Pendulum bobs of equal radius, but different masses, made of cork, wood, brass, steel, etc.; string, one- and two-meter sticks; electric stop clock; balance scales; goniometer (on the back of this lab manual); 2 x 1 cycle log-log graph paper.
5. PROCEDURE:
To simplify and systematize the data-taking and analysis, confine your experimental values for pendulum length to the values
15, 30, 60, 100, 200 cm
or:
20, 40, 80, 150, 300 cm
depending on the maximum length of pendulum your laboratory situation can accomodate. Investigate at least five or six different lengths.
Use values of amplitude angle of
5, 30 and 80 degrees,
measured from the vertical.