Lab 4 Physics 131

UIC Physics Department Physics 131 A'ua N/;ulbcw ‘V(r-f'),//rl 7(,,,,7/4‘,7;,,_/‘ 2/ 2 NAME & SECTION ° ' DATE ; y - T : Physics 131 -Lab# 1 Title n/vjia//) o Pre - laboratory Assignment Carefully read the entire lab manual for this lab and answer the following questions. 1. Describe in your own words the overall goals of the lab. e gierall - gon iftuise gl fo uhoersinnd Pajnalds' pamoer an d also f, undergand da? ree anel it 1 le’(:lun!(/{ of b jects with oli frup - rmedEes, 2. Identify the physics concepts that you will learn about or test in the lab. T physicS conlePt wolil Le Feoynolds hum'ber, Dra 9 /bv(e, velc()}y ; Standoard deicy , and evrer ana ly «is wWe dlse witl Fird cut p reladTenChip bedoee r Prg7 Ferce ard u{.’fijff\, Page 1 of 2

UIC Physics Department Physics 131 PreLab ) [ 1 i he ot nes ( 3. Describe briefly what you will measure in the lab and make your predictions of the outcome . the important measurements in the experiment. Your predictions do not need to be correct to earn credit on this part, but you should explain your reasoning. r Nl > i 7 7.4 ot we wil }/,:' w /fif."(lu'/f . amoynt of ,'j/f’f’i favée 1o o xey le / Frm He ¢ ¢ / ‘,‘.—,yl / { “ N ne /// £ e prelg N of }J“ o e rllers nase, o ,Az/’, l2rce. s 1150 In order to receive credit for this pre-lab report, you must have your pre-lab completed before the lab session begins, and show it to your TA so they can verify that you have done it. If your TA has not seen your pre-lab and confirmed that you have it completed at the beginning of your lab session, you will get a 0 for the pre-lab component of your lab report. As a record, please have your TA sign your completed pre-lab report below. If you have completed this electronically, and the TA cannot sign this document, write “Signature on last page of lab report” below, and have the TA write "Prelab Completed:” followed by their signature on the last page of your lab report. "‘//,v»- ( g /'V 7\ )( = TA Signature: g Page 2 of 2

UIC phy: cs Department ) 131 Initial Setup - Make sure that Pasco interface and computer are turned on and the motion sensor is plugged into the interface. The yellow plug must be inserted into digital channel 1 and the black plug into digital channel 2. - Open CapStone program, then click “Hardware Setup” button on left side of “Tools” panel . - Click on digital channel 1 of the interface picture S0 GEEE B and add “Motion Sensor II". [od o Bisod - Drag onto the “Display Area”. - Click "<Select Measurement>" on the y-axis of the graph and choose “Position (m)", then click “<Select Measurement>" on the x-axis of the graph and choose “Time (s)". - Click “Record” button to activate the motion sensor. You should hear a series of rapid clicks. Record - Test out the motion sensor by holding a book facing, and approximately 15-20 cm away from, the sensor. (The sensor does not measure distances closer than ~ 15-20 cm.) Move the book to a distance of ~ 1.5 meters from the sensor and then back to its initial position. - Then, click “Stop” button E when you are done. {\ Position vs time curve should appear in the graph area. If it does, then the apparatus is ready for use. If it does not, contact immediately your Lab TA or Lab Assistant. You may want to click the “Scale axes to show all data” button at the left end of the tool bar above the graphs. If you do not obtain a clean trace, try again, being careful to keep the book directly in front of the sensor. Experimental Procedure 4. Before you start the experiment, find the mass of single coffee filter. To do that, use a digital scale to mass all eight filters so you can divide to get an average mass for one filter. 5. Calculate and record the mass and its uncertainty, o, of each set of filters in Table 1. Estimate the uncertainty as readability of the digital scale used in this experiment (1 gram) divided by number of filters. One lab partner must be in position to drop the filters along the path of the detector. 6. Calculate the |fid,ag| for each set of filters, which is equal to its weight, then use propagation of uncertainty (see Experiment 1) to calculate uncertainty, o, in drag force Record the results in Table 1. Inertial Drag Force and Terminal Velocity Page 2 of 6

Uic p Phy:s Department Physi 800d to be analyzed. Then click the “Stop” button Y : 3011 can change the axis scale (value between tick marks) to zoom-in or zoom-out. Todot XIS you would like to scale and then drag away from origin to decrease the scale (zoom-in Origin to increase the scale (zoom-out). 8. Select the part of the graph you would like to analyze. You should get a graph th Figure 4a, 9. Click “Data Highlighter” . data points that lie on a straight line. 10l Click the down arrow on “Curve Fit" | > < and select the “linear: mx + 4" to fit the selected data points. Find the optimal height from which you will drop the filters, F}t:r a go_od result, at least ~ 1/3 of all data points should lie along a straight line (see Figure 4b). The slope, m, of the line of best fit will give you the value of the terminal velocity. 11. Repeat three times steps 5-9 for each set of filters and recprd the values of terminal velocity and its uncertainties in Table 1. 12. lfor each set of filters, calculate the average terminal velocity and its standard deviation, a,,, and record the results in Table 1. We expect that the equipment, since it is the same for all measurements of terminal velocity, will have a constant precision. However, there are two possible ways to interpret this: either there is a constant uncertainty (in m/s) for all terminal velocity measurements, or there is a constant relative uncertainty, g, /vr, (or percent uncertainty) across all measurements. To compare these possibilities, look at the standard deviations of the terminal velocity of a single coffee filter, and compare with the g, for 5 filters. If they ZI Click "Record” to activate the motion sensor. Now, your lab partne i ter(s) fall away from the detector zone, the graph will look “smashed”. easurement several times (without stopping recording) until you will get a | horatory F ’——"/'m)’—l—f the r should drop the repeat the In this caseé, graph that isa reasonably hat, click on the ) or toward the at looks something like . Then, you can resize the high-lighter rectangle and move it to select the Figure 4. 1.0 @ 7 B 724 “ 205 ol Z / a P /’/l : 338 340 34z Time (s) i (b) -~ E o o E 0.5 = pe a 1/ 338 34.0 382 Time (s) are roughly the same, then you can conclude that the technique you used to measure vy has a random error of constant size; if they are different but in such a way that g,,. /vy is the same for both 1 filter and 5 filters, you can conclude that the percent error is constant. Inertial Drag Force and Terminal Velocity Page 3 of 6

UIC Physics Department Ph 1 Laborator Data Analysis 13. Will you assume a constant error or constant percentage error for your terminal velocity measurements? Justify your approach. g tannet { L 1 carxktaa /10 " 4 e it Ay Y rr/ ol L4 [yjal & ¢ ¢ a4 [fLasnce ik - ! 7 N vinod VY oy i / p 4 4 Nz b o 4 - 14. Copy the last four columns in Table 1 to LibreOffice Calc worksheet. s 15. Use v; and Farag columns to generate a scatter plot and make sure to include the error bars for both vrand Fgypq. 16. Instead of a linear trendline fit, apply a Power trendline fit (y = Ax™) to the datf points and record below the fitting parameters (including units) and regression coefficient squared, R?(a measure of how well the regression line represents the data points): /) f - A= ¢ ‘: ( ) n= [0 R2=W. 17. Then, apply a linear trendline fit (y = mx + b) to the data points and record below the fitting parameters ()including units and regression coefficient squared, R?: y¢f 2 m=_4517 ( ) b= —22 ¢ ) rz= 0 2 18. Does this curve fit better or worse than the fit using Power? State your reasoning clearly. Is the graph linear, quadratic, or neither? Are your error bars small enough to confidently distinguish between the two? State your reasoning. Wu Powor it ,//,/(/ £ols bethy eraiue SN ipus .4/_'/ 175 ufpnast Z, phict oLant thal 1wvs - fepvusSigyn ing Lpre ren ) e y 92 ) r . y Hu (/r‘ fa Lathr /,‘ 7889 > 0. v //;/. { e // QPh Is Jiaudr L/ 7 2 / [ . .:?/.5/ Jhe _evray haJ ol Smal __engugh 7o car™clor ‘./y Aichi Qu ch ‘ J ket ten ; e [l o /1/—1 . /,‘J(‘/ ard_ Bt Chay And viciAe., 5 19. Do your experimental data support your prediction in step #3? Explain. | P ol Aol /’5, My expelind} tal _datu Suppdtls My wolicationS i Skp #2. Thave 15, G ¢ubdraflc gipudihet [ eteen s _/,rr; fird _aud A (,, 1 1/ WU (WP Inertial Drag Force and Terminal Velocity Page 50f6

UIC Physi, Department Ph A 20. Based on your observations, do the filters experience viscous or inertial drag or both? Do your expe rimental data support your prediction in step #2? Justify your conclusion. L {x el et inte g 21. We have ignored the force of buoyancy for this lab - approximately how large of an error did that introduce? Was that error significantly smaller than the other sources of uncertainty? Justify your answer. / J /s M Y td ni6e ol e 1y Zioni flrant. efrr brcey ’ 14 _Af o Vit y mall ) Y Nt [k o) kb 4000 2 VoY rne | (4 2 2y ‘ ¢ Y [ - 1 4 A o ylhay 4 1Tl “r /r/’J/‘}/ o f /1 / » 45 I (St # (vl fi~ /f’/r;w./ ol LY { - /L / it make fng ' Al 1w patt, 22. Discuss some other contributions to the uncertainties in measured quantities of vy and Fypap (Remember, “human error” is generally not an acceptable answer by itself. If you made any errors, you should go back and do it correctly, and if that isn’t possible, you need to state exactly what the error was that you made and estimate how large of an effect that error had.) (v conMnding 12 Mt uncevtaintiel iy pususured /;/ru"‘i” could inyelee Hl Hlfrs [ '/fj Julside e /Mj& of stnioy, Abn- 2L jaitial velgety. 4 Y pop-upfmm g it heigat o7 b, When uploading to Gradescope, you must combine everything into a single pdf file, and match the pages to the questions. Make sure you do this correctly - any question/table/graph/etc. which is not correctly matched will be penalized by 20%. Inertial Drag Force and Terminal Velocity Page 6 of 6