Projectile Motion

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1、STAGE2PHYSICSRonAim:Todeterminehowthedifferentlaunchanglesaffecttherangeofaballwherethelaunchheightisthesameasthelandingheight.Hypothesis:∵usinθ=u(y),ucosθ=u(x)∴withthesameinitialspeed,u(y)isincreasingasθincreases.Oppositelyu(x)isdecreasingasθincreases.

2、Therangeofprojectileisthemaximumwhenthelaunchangleis45°andtherangeisdecreasingasthelaunchangleincreasesordecreases.Apparatus:lProjectilelauncherlLaunchballlClamplMeterrulelLightgatelDateloggerVariables:lIndependentvariable:launchanglelDependentvariable:

3、rangeofprojectilelControlledvariable:thesameapparatus,nowind,orotherforceeffectsProcedure1.Afterreadingtherestoftheprocedure,describeandexplainthesafetyconsiderationsforthisinvestigation.2.Setuptheapparatusasshown.3.Recordthediameterofthelaunchball.When

4、theballisfiredthedataloggerwillmeasurethetimeforthisballtopassthroughthelightbeam,theinitialspeedoftheballcanbecalculatedbydividingtheballdiameterbythethistime.4.Prepareatargetconsistingofamagazineandcarbonpaper,ensuringthatthelandingheightisthesameasth

5、elaunchheight.5.Settheelevationto45°,fireseveralshotsandrecordtherangeandlaunchangle.6.Repeatforangles15°,25°,35°,55°,65°,75°.Results:Angle(°)Range(m)Time(*10^-3s)Launchspeed(m/s)150.9121.0631.0253.403.623.54Average1.0003.525.101.5653.89251.6433.521.885

6、3.48Average1.6983.634.942.1043.53352.0633.602.0113.66Average2.0593.604.992.1953.66452.1813.672.2153.50Average2.1973.614.972.1533.57552.0053.692.1233.33Average2.0943.535.081.8642.96651.7953.521.7433.74Average1.8013.415.271.2323.54751.2433.561.1453.43Aver

7、age1.2073.515.11Analysis:1.2.3.usinθ=u(y),ucos=u(x)t(y)=0-usinθ-g*2t(x)=RangeucosθRangeucosθ=2usinθgRange=2usinθ*ucosθgRange=u^2sin2θg∵themaximumvalueofsin2θis1when2θ=90°∴θ=45°whentherangeisthemaximum.Evaluation:Inthisinvestigation,therearesomerandomerr

8、orswhichcanbereducedintheprocedure.Thehorizontaldirectionofthelaunchdeviceshouldbeinthesamewaywiththerulerwhichisusedformeasuringtherange.Itwillbegoodtouseastringtoconnecttheendoftherulerandthelaunchdeviceformakingsureifthedirect