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Figure A: Arrangement of equipment and definition of distance p and q.; q is defined as the distance betw

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Experiment 2: Centre of Mass

Objectives:

a! o investigate the uniformly distributed mass.

b! o measure the mass of a metre ruler using the principle of centre of mass and

static equilibrium.

Equipment:

)etort stand with clamp* a good metre rule* small mass carrier* slotted masses (%0g +

%* ,0g + ,! and thread.

Procedures:

a! he clamp of a retort stand is fi-ed so that its bar is horiontal.

b! A mass carrier is tied by using a thread to the end of a meter ruler as shown in

the diagram. he mass carrier is located close to the end of the ruler.

c! he mass carrier is hung near one end of the metre rule and the metre rule is

placed on the bar* as shown in the diagram.d! he ruler is moved until it balances horiontally.

e! he positions of the mass carrier and the pivot on the ruler are recorded.

f! he e-periment is repeated five times with additions of %0g slotted mass each

time.

g! All the data is recorded in able %.

h! he mass of the ruler is measured using an electronic scale. his value is used

as the real value.

i! he mass of the ruler is calculated using the principle of static equilibrium.

Evaluation:

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he chief uncertainty arises from getting the beam to balance horiontally and

reading the position of the pivot. he position has to be found by trial and error* and

read from a scale that lies above the actual point of contact.

Table 1: Experiment data.

/ass of ruler from electronic scale: g

#o % , 1 5 2

otal carrier mass (g! %0 ,0 0 10 50 20

'osition of carrier

(mm!

'osition of pivot

(mm!

3istance p (mm!

3istance q (mm! Average

/ass of ruler (g!

Tass:

a! 4alculate the percentage of error for this e-periment. dentify the sources of

error.

6ources of error:

%. he metre rule is not perfectly horiontal.

,. he e-act location of pivot is not a contact point.

. 'arrala- error when the the eye level is perpendicular to the scale.

b! $ive a suggestion to improve the accuracy of this e-periment through

improvement of the methodology.

7se a longer metre rule so that the percentage error of p and q would be

smaller.

Conclusion:

3raw your conclusions according to the ob8ectives of the e-periment.

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