Acceleration Lab Teacher s Guide

Transcription

1 Acceleraion Lab Teacher s Guide Objecives:. Use graphs of disance vs. ime and velociy vs. ime o find acceleraion of a oy car.. Observe he relaionship beween he angle of an inclined plane and he acceleraion of a oy car on he inclined plane. Maerials: Each group mus have: Toy car, m inclined plane, noebooks, meer sick, sopwach Mehods: The mos difficul par of his lab will probably be iming he cars. Make sure ha sudens have one person wih a sopwach and wo people marking posiions. When he car is released, he imer sars iming and calls ou every second. The sudens marking he posiion will do so by placing a finger where he car is when he imer calls ou a second. For insance: r Disance marker A Disance marker B s marks wih lef hand wais s marks wih righ hand wais s wais marks wih lef hand s wais marks wih righ hand Afer doing a rial run o make sure hey know how o make he measuremens, sudens will ake daa for he inclined plane a wo differen angles (resed on or books). They can hen calculae he disance raveled in each second, he average velociy for each ime inerval (disance raveled in second divided by second), and he acceleraion (by graphing velociy vs. ime). To deermine deceleraion, sudens will do he same hing, excep ha hey won begin marking posiions unil he car has reached he boom of he rack. This lab has many chances for error. If an inclined plane is warped, he acceleraion won be consan. Fricion will lower he acceleraion. Timing is difficul. This is why hey do a pracice run before acually aking daa. If he car is moving oo fas o ge accurae posiion measuremens, ry lowering he board. If fricion is so large ha he car acually slows as i goes down he plane, ry raising he board, or geing a differen car. Sudens should also accoun for error on heir handou.

2 Name: Acceleraion Lab Objecives: In his lab, you will be sudying acceleraion due o graviy by observing Ho Wheels cars on inclined planes. Your goal will be o deermine he acceleraion of he car wih he inclined plane a differen angles. The lab will show how graphs of displacemen versus ime and velociy versus ime can be used o find acceleraion. Maerials: Ho Wheels car, m inclined plane, noebooks, meer sick, sopwach Procedure: ) Begin by designaing one person o be he car holder, people as disance markers, one person as a recorder, and one as a imer. ) Raise one end of he inclined plane by placing he end on one noebook. ) Trial run: Have he car holder hold he car a he op of he ramp (a 0cm). When he car holder releases he car, have he imer begin iming. The imer should call ou one-second inervals. Have he disance markers mark he posiion of he car wih a finger for each inerval. HINT Each disance marker has wo hands, so if he uses a finger on his lef hand o mark of inerval and he righ hand o mark off inerval, he nex disance marker can use her wo hands o mark off inervals and, ec. In he able below, record your daa: Table. Daa for Trial Run ) If you were no able o obain he posiion for each ime inerval, ry again unil you have a sysem ha enables you o ge all four posiions. 5) Now you are ready o begin aking daa. You will be repeaing he above procedure for wo differen heighs, and for each heigh, you will be doing hree rials and averaging your daa. 6) Keep one end of he plane placed on one noebook. Le he car go down he ramp imes, and record your daa for each run in Table. Take he average posiion for each ime and ener i ino he able. Then for each ime inerval, calculae he disance raveled in second. This is simply he average posiion minus he previous average posiion. For he firs ime, i will be average posiion minus zero cm, ec.

3 Then calculae he velociy for each ime inerval by aking he displacemen divided by he ime inerval (he inerval is second each ime). Table. One Noebook Run Run Run Ave. Disance raveled in second Velociy 7) Now repea he procedure for wo he plane raised on wo noebooks. Table. Two Noebooks Run Run Run Ave. Disance raveled in second Velociy 8) Now do an experimen o find he deceleraion of your racecar. Place he car a he op of he ramp (wih noebooks), and le i go. Begin aking daa when he car reaches he able, and record he posiion (from he lower end of he ramp) as you did before for seconds. Do his hree imes wih he ramp raised he same heigh and record your daa in Table. Calculae he average posiion, displacemen, and velociy in he same way as before. You may have o move your ramp o he floor and raise i even more o ge enough horizonal disance o measure deceleraion. Table Ave. Disance raveled in second Velociy Analysis: ) Creae a posiion versus ime graph for your wo heighs (number of noebooks) using he average posiions you calculaed and aach he graph o your repor.

4 ) Now make velociy versus ime graphs for your wo heighs and aach hem o your repor. ) Calculae he acceleraion of he car for each heigh by finding he slope of your velociy versus ime graphs. Repor he acceleraion here, and show your work on your graph. One noebook: Acceleraion = m/s Two noebooks: Acceleraion = m/s ) Make a posiion versus ime graph for your daa colleced in Table. 5) Make a velociy versus ime graph for your daa colleced in Table. 6) Calculae he acceleraion of he car for he daa in Table by aking he slope of he velociy versus ime graph for hese daa. Repor he acceleraion here, and show your work on your graph. Acceleraion is negaive for deceleraion. Acceleraion = m/s Quesions: ) Wha is he main difference beween your posiion vs. ime graphs and your velociy vs. ime graphs for Tables and? ) Wha is he main difference beween he posiion versus ime graphs for ables and and he posiion versus ime graph for able? ) Wha is he main difference beween he velociy versus ime graphs for ables and and he velociy versus ime graph for able? ) Draw a posiion versus ime graph for acceleraion and deceleraion. Acceleraion Deceleraion d d

5 5) Draw a velociy versus ime graph for acceleraion and deceleraion. Acceleraion Deceleraion v v 6) How does he angle of your inclined plane affec he acceleraion of your racecar? 7) Wha are some facors ha migh inroduce error ino his experimen? 8) How could you make his experimen beer? 9) Wha would a disance vs. ime graph look like if you sared aking daa a he op of he ramp and coninued afer i reached he boom of he ramp? How abou velociy versus ime? d v

6 Acceleraion Lab Prelab Quesions Name:. Wha are he goals of his lab?. Describe how you will ake daa o deermine he acceleraion of he oy car.. Fill in he remaining porion of he able below and hen describe how you would deermine he acceleraion. Run Run Run Ave. Disance raveled in second Velociy. When do you begin marking he posiion of he oy car when you are aking daa o deermine he deceleraion?

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