Physics: Page 1 of 2
Investigation: Addition of Vectors
Aim: Todemonstrateadditionofvectors
Equipment: Forcemeters/springbalances(%2)
Weights(atleast45)StringProtractorRuler
Method: 1.
Cutsomestringandtietothemetersasshown.Attachweights.2.
Holdthetwometersupintheair.3.
Adjusttheweightssothatitisdirectlybetweenthetwometersalongthe
string(usearulertomeasurethedistances).4. Measure the angle
between the twometers (marked on thediagram)
usingaprotractor.5. Read the forcesalong each component from the
twometers,and record
thisinatable(readings1and2).6. Using the same set of weights,
setup the equipment by hooking the
weightsontooneforcemeter/springbalance.7.
Readtheweightforceoftheweightsandrecord(reading3).
RiskAssessment:
Thisisarelativelysafeexperiment.However,youmustbecarefulnottodropalargeamountofweightsonsomeoneaccidentally,ortoswallowtheweights.Stringleftcarelesslybehindmaytripsomeoneunsuspectingly.
Physics: Page 2 of 2
Results:
Themeasurementstakenfromtheforcemetersarerecordedbelow:
Reading Number 1 2 3 Force (N) 0.8 0.8 1.0
Angle between the two meters = 90
Analysis: Separating the forces that are at an angle to the
horizontal into
theircomponentvectors:xisequalinbothcasesbecausetheweightsweremeasuredtobeplacedinthemiddle(i.e.thesetupissymmetrical).
cos 45 = x
0.8
x = 0.8 cos 45
Totalforcealongverticalcomponentinthefirstreadings: 2x = 1.6 cos 45
= 1.1N (to 2 sig. fig.) Force measured downwards (reading 3)
Discussion:
Inaccuraciesarepresentreadingsonthemeterscanonlybemadetothenearest0.2Nbecauseofthemarkingsontheside.
Theforcemeterswerenotaccurateduetowearandtearasspringswerestretched.
Readings from protractor is inaccurate because the person who
washoldingthespringsdidnothaveasteadyhandandbecauseit
ishardtomeasuresomethinginmidair.
o An improvementcouldconsistofusingretortstands tohold
thespringmetersup,insteadofsomeoneholdingthem
The experiment as a whole can be improved by taking
moremeasurementsandreadingsbyalteringtheangleatthemiddleandusingavarietyofweights.
Thisinvestigationappliedtheadditionofcomponentsofvectorsintoreallifeadditionofforcesalongonedimensioncanalsobeinvestigated.
Conclusion:
Thetheoryregardingtheadditionofvectorsissupportedbythisinvestigation
becausetheadditionofthedownwardscomponentsofthevectorsatanangleapproximatelyequalsthedownwardsweightforcemeasured.
