A B C D E F 1 Radius (cm) Washers Time (s) 2 72.89 18.73 Mass of rubber stopper 11.76 3 72.89 4 20.19 Mass of 4 washers 30.65 4 72.89 8 13.95 Mass of metal plate 0.56 72.89 8 14.25 6 72.89 12 11.32 7 72.89 12 11.36 8 72.89 16 10.3 9 72.89 16 10.34 10 72.89 20 9.07 11 72.89 20 8.97 12 60 8 13.43 13 60 8 13.25 14 50 8 12.34 15 50 12.26 16 40 8 10.73 17 40 8 10.94 18 30 8 8.9 19 30 8.76Purpose: To determine the relationships between centripetal force, and period of revolution for an object in a state of uniform circular motion. Hypotheses: Predict the proportional relationship between period and radius. Predict the proportional relationship between period and centripetal force. Material: 1 rubber stopper 20 steel washers 2 paper clips 1.5 m nylon string 1 glass tube metre stick stopwatch balance safety googles Procedure: 1. You will work in groups of 2 to 4. 2. Tie a rubber stopper to one end of the string. tie a small knot in the other end of the string, and pass the string through the tube. 3. Place 4 washers onto the knotted end of the string and use one paper clip to hold them in place. 4. Pull the string through the tube so that the centre of the rubber stopper is 70 cm from the top of the tube. 5. With the string pulled taught, place the second paper clip approximately 1 cm below the bottom of the tube. 6. Create a data table to record the number of revolutions, elapsed time, radius of revolution, number of washers on the string, and all relevant masses. 7. `Make sure that everyone is wearing safety goggles. 8. Holding onto the string just above the washers, swing the stopper in a horizontal circle above your head. 9. Slowly let go of the string and try to maintain the upper paper clip 1 cm below the end of the tube in order to maintain the radius of revolution as set in step 4. If the paper clip moves downward, slowly increase the swing speed. If the paper clip moves upward, slowly decrease the swing speed. 10. Once you have established the constant swing speed required to keep the paper clip 1 cm from the end of the tube, measure and record the time for 20 revolutions. 11 Repeat steps 8- 10 in order to consider an average of two values in your analysis. 12. Add 4 more washers to the end of the string and repeat steps 4 -11. Continue this procedure up to a total of 20 washers. 13. Repeat this procedure using & washers and a radius of revolution of 60 cm. 14. Continue this procedure for radii of revolution of 50 cm, 40 cm, and 30 cm.Analysis: Calculate the average period of revolution .Bravitational force for each experimental combination. Summarize your experimental results in two holes in SI base units): * period versus radius of revolution for a constant centripetal force period versus centripetal force for a constant radius of revolution Determine how well the experimental relationships match your hypothetical Proportionalities by determining equations based on the experimental results and calculating the experimental error for the proportionality constants. Discuss sources of error in this experiment and whether they would tend to increase or decrease the experimental proportionality constant. Other Group Members: EVALUATION REQUIREMENTS One report is required from each student and must include the following: . Hypotheses including two proportionality statements. (4 THK) . Observations of measured quantities for all experimental trials. (6 APP) . Analysis including the following: o sample calculation for period and gravitational force (4 THK) two summary tables of experimental results (in SI base units) (4 APP] o determination of two experimental equations (in SI base units) (6 APP) calculation of experimental error for proportionality constants (4 APP] o discussion of sources of error (4 THK) Communication including the following: o neatness, completeness, logical formatting and organization (4 COMM) a consistent correct use of significant digits, units, uncertainty, and terminology (4 COMM] Include this page as the first page of your report. No additional title page is required.Analysis: two summary lables: 1(m ) T (s) F. (N ) / T (s ) F man'r 1 1 1 T= CD experimental equations. T= kr plot Tusr and Tis F. consliml I, while generate log- log values shoot Fines plot log(Thus log(r) and log(T) us. log (Fc) get line of best fit equation for both graphs ( y=mx+b ) - determine "hand"" values from "band "m experimental error : calculate theoretical values of k using measured masses, radio, etc." Terror : exp 'R' - theo't' theo'k" - souras of error how dors reality differ from assumptions factors not considered in theoretical equations, but encountered in really