MOTION DETECTORS GRAPH MATCHING LAB PRE-LAB QUESTIONS

Transcription

1 NME: TE: LOK: MOTION ETETORS GRPH MTHING L PRE-L QUESTIONS 1. Read he insrucions, and answer he following quesions. Make sure you resae he quesion so I don hae o read he quesion o undersand he answer.. Selec he objecie ha you hink is mos imporan and resae i.. Wha is he name of he applicaion we will use?. In par II, sep 8 (refer o lab procedure), here is a posiion-ime graph represening a moion. How much disance is represened by ha graph? How much displacemen? d = Δ = 2. Use a coordinae sysem wih he origin a he moion deecor and posiie posiions in fron of i. Skech he posiion s. ime graph for each of he following siuaions:. suden sands sill a couple of meers in fron of he deecor.. suden sars near he deecor and walks away a consan speed.. suden sars far from he deecor, and walks oward i a consan speed.. suden sars a res, near he deecor, hen moes away geing faser and faser. 3. Skech he elociy s. ime graph for each of he following siuaions:. slow car moing away from he deecor.. fas car moing away from he deecor.. slow car moing owards he deecor.. fas car moing owards he deecor.

2 Moion eecors - Graph Maching One of he mos effecie mehods of describing moion is o plo graphs of posiion, elociy, and acceleraion s. ime. From such a graphical represenaion, i is possible o deermine in wha direcion an objec is going, how fas i is moing, how far i raeled, and wheher i is speeding up or slowing down. In his eperimen, you will use a Moion eecor o deermine his informaion by ploing a real ime graph of your moion as you moe across he classroom. The Moion eecor measures he ime i akes for a high frequency sound pulse o rael from he deecor o an objec and back. Using his round-rip ime and he speed of sound, you can deermine he disance o he objec; ha is, is posiion. Logger Pro will perform his calculaion for you. I can hen use he change in posiion o calculae he objec s elociy and acceleraion. ll of his informaion can be displayed eiher as a able or a graph. qualiaie analysis of he graphs of your moion will help you deelop an undersanding of he conceps of kinemaics. OJETIVES nalyze he moion of a suden/car moing. Predic, skech, and es posiion s. ime kinemaics graphs. Predic, skech, and es elociy s. ime kinemaics graphs. MTERILS Power Macinosh or Windows P Logger Pro Vernier Moion eecor 2 Moor cars: slow and fas

3 PROEURE Par l Preliminary Eperimens 1. onnec he Moion eecor o he US por of he compuer. 2. Sar up he program Logger Pro (find i by going o he apple menu, and selecing Recen Iems ) 3. Place he Moion eecor so ha i poins oward an open space a leas 4 m long. 4. Go o he File menu a he op of he Logger Pro window. Selec Open, hen Physics wih Vernier, and hen selec 1a graph maching.gmbl. (If a any ime he compuer asks if you wan o sae, selec on Sae. ) One graph will appear on he screen. 5. Produce a graph of your moion when you walk away from he deecor wih consan elociy. To do his, sand abou 1 m from he Moion eecor and hae your parner click ollec. Walk slowly away from he Moion eecor when you hear i begin o click. 6. Try o mach he shape of he posiion s. ime graphs ha you skeched in he Preliminary Quesions secion by walking in fron of he Moion eecor. 7. Try maching he following graphs. (You can epec o hae o mach one of hese during a quiz or a es). We will only spend 15 minues maimum rying o mach hese. Eeryone in he group should gie i a ry. posiion posiion posiion ime ime ime posiion posiion posiion E F ime ime ime

4 Par Il Posiion s. Time Graph Maching 8. Open he file 1b Graph Maching. The posiion s. ime graph shown will appear. 9. escribe how you would walk o produce his arge graph. 1. To es your predicion, choose a saring posiion and sand a ha poin. Sar daa collecion by clicking ollec. When you hear he Moion eecor begin o click, walk in such a way ha he graph of your moion maches he arge graph on he compuer screen. 11. If you were no successful, repea he process unil your moion closely maches he graph on he screen. If a priner is aached, prin he graph wih your bes aemp and ask a eacher o iniial i. 12. Open he file 1c Graph Maching. and repea Seps 7 9, using a new arge graph. 13. escribe how you would walk o produce his arge graph.

5 Par IlI Velociy s. Time Graph Maching 14. Open 1a Graph Maching again; collec and record he following daa:. slow car moing away from he deecor.. fas car moing away from he deecor.. slow car moing owards he deecor.. fas car moing owards he deecor. E. Wha do you hink a elociy-ime graph will look like if he car is a res? Why? Try i. Were you righ?

6 Par IV Velociy s. Time Graphs for acceleraed moion - Possible Era (if ime allows i) Using cars and ramps, reproduce each of he moions in he elociy-ime graphs below. escribe he moion of he objec. el (m/s) ime(sec) escripion: escripion: el (m/s) ime(sec) el (m/s) ime(sec) escripion: el (m/s) ime(sec) escripion:

7 Name: ae: 1 poins for conduc of lab, 1 poins for answers in complee senences 2 poins oal Read and answer all pars of he quesions. NLYSIS MOTION ETETOR GRPH MTHING L Par II Posiion s. Time Graph Maching 1. escribe how you walked for each of he graphs ha you mached. e accurae and precise. Graph 1b: Graph 1c: 2. Wha pars of he graph are easy o mach? Wha pars are difficul? 3. Wha does he slope of a posiion s. ime graph represen? Include a discussion of posiie and negaie slope. 4. Wha ype of moion is occurring when he slope of a posiion s. ime graph is zero? 5. Wha ype of moion is occurring when he slope of a posiion s. ime graph is consan (in oher words, when he line is sraigh)? Par III Velociy s. Time Graph Maching 6. Wha abou hese graphs surprised you? Why? 7. escribe he line of a elociy graph ha when he car is moing a a consan speed. Wha is he slope of his line?

8 8. escribe he difference beween a elociy-ime graph of a car moing away and a car moing owards he deecor. 9. escribe he difference of a elociy-ime graph beween a fas car and a slow car. 1. How would a elociy-ime graph look for an objec ha is speeding up? 11. Wha would a elociy-ime graph appear for an objec ha is slowing down? 12. Why can you hae a negaie elociy (below he -ais) bu NOT a negaie posiion? nd in conclusion 13. ommen on he lab. This is no an opional quesion. Wha par of i mos helped you o undersand moion graphs? Wha aspec of graphs sill puzzles you? How could we modify he lab o help clear ha up?