7BOBO-dHHHHHH-4H--,p - -Zl`rxHH(FG(HH(d'@-l /:Ax-,-LxxA*B*< *"*F*Xl*x**d*(c-t-8*,:-9v *-!4 }DSET[@qI---<y-vly-/xy--vy-|F)*LMop*+LST'lX , - h & W X , ]   JK\  Am2UDE    , - M X  2           ' W [ s v     _ ` b k             .               |            8 T [     D        <--- ---L DATE___________ NAME OF GROUP MEMBERS __________________________ __________________________ __________________________ UNIT 1: LEARNING PROBLEM-SOLVING TECHNIQUES LABORATORY ACTIVITY 3 DESIGNING A TIME-MEASURING DEVICE GROUP DATA SHEET The members of this team should use the data on this sheet to complete their own lab reports. The secretary should turn this sheet in when all team members have the information. You would like to design a simple device for measuring short periods of time. The device is to be rugged, portable, and inexpensive. You learn from your friend, who is taking a physics course, that a pendulum of a fixed length always takes the SAME time for a complete back-and-forth swing. You have a plumb line and decide to use it as a pendulum. FIND: The length of line that will give you a complete swing lasting approximately 1 second. NOTE: Measure the length of the string that swings. Provide a clear swinging path for 3 to 12 inches of string, with a stable tie-down point at the top (for example, tie it to the back of a chair, or drape it over the edge of a table.) How to count a complete swing: A complete swing (as illustrated) is a back and forth cycle. So the counting procedure will be as follows: Pull the weight back a few inches, release and start timer The weight will swing away and return -- count one The weight will swing away and return -- count two --- --- --- --- The weight will swing away and return -- count ten and stop timer. * Use the stopwatch to measure the time required for10 complete swings. * Divide this time by 10 to get the time of one complete swing. This time is called the pendulums period. * Vary the length from 3 inches to 12 inches, in increments of 1 inch, and determine the period for each length. * For each length record the following in a table: the pendulum length , the time for 10 complete swings, and the period in seconds. * Have someone in your group agree to do 50 chair-stepping exercises (stepping onto and off of a chair 50 times). Use your pendulum -- 10 inches in length -- and a stopwatch to measure how long the exercise takes. Compare the result of your pendulum clock to the result of the stopwatch. How did your clock do? Understand the problem 1. What are you trying to find? *** a. I am trying to find:______________________________ _____________________________________________ 2. What data do you now have to solve the problem? *** a. Why are you using a pendulum? _____________________________________________ _____________________________________________ *** b. What features make a pendulum an advantageous device to use?_________________________________ _____________________________________________ *** c. How can a pendulum be used as a timing device? _____________________________________________ _____________________________________________ _____________________________________________ Develop a plan 1. What additional information do you need to solve this problem? *** a. To determine the length of string that will swing with a period of one second, what variety of string lengths do you need to use?_______________________________ ___________________________________________________ 2. Does finding any of this information involve solving other problems? 3. Are there any graphical methods you can use? *** Yes or No?___________________ 4. What mathematical methods can you use? *** a. After timing 10 swings (of one string length), how do you get the time for one swing (ie., the average)?_________ _____________________________________________ _____________________________________________ 5. Is equipment available that you can use to find the needed information? *** List the equipment you have been supplied with: ____________________ ____________________ ____________________ ____________________ ____________________ Carry out the plan 1. Solve the problem, showing all of your work. *** MAKE A TABLE FOR THE DATA GATHERING (worth 10 pt.s!) (First one is done for you.) String Length (inches) Time for 10 swings Time for 1 swing 3 5 sec 0.5 sec *** What length of line will give you a complete swing lasting approximately 1 second?__________________________ 2. Can you make a rough estimate for any or all parts of the solution? Check the results 1. If you made rough estimates of the solution, compare the estimates to your calculated results. DSET|(H->"9 *6*>"9DSET(H-H9y>9z6*=9DSETRE@E----h   F-FOn this team paper, you only have to complete the sections marked ***