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T E N S I O N A N D U P T H R

Object ive today:

1. Descr ibe what happens you stretch a spr ing

2. Explain what is mean by

3. Explain the e last ic l imit

. Expla in why th ings ! oat

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STRETCH A SPRING• For loads of up to 10 N

the graph is a straight linethrough the origin.

•   This means the pullingforce is proportional tothe extension produced.

•  ‘Proportional’ means thatif, for example, the pullingforce doubles, theextension doubles as well.

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TENSION#orce that is transmittedthrough a string, rope,

cable or wire when it ispulled tight b forcesacting from opposite ends.

ELASTIC LIMIT The maximum $orcethat can applied to anelastic ob"ect to return toits original length whenthe force is remo#ed.

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Different springs

•  Some springs are strongerthan others.

•  A stiff spring can be pulledwith a bigger force beforereaching its elastic limit.

•  Which spring is stiffer, A orB?

A

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Stretching a rubber band

•  A rubber band does not

stretch at a steady rate whenpulled with an increasing force.

•  The graph line is notstraight.

•  The pulling force is neverproportional to the extension.

•  Try stretching one.

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 ACTIVITY 1. $easure the weight of the stone in the air.

%. Full submerge the stone in the water and reweight of the stone.

&. 'ecord the result in the table below.

(eight of stone , ()N*

+n the air +n water

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UPTHRUST

 The upward $orce that a liuid or gas exa bod -oating in it.

upthr

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FLOAT OR SINK?

1. When weight is greater than upthrust, the obje

……………… in the liquid

2. When weight is equal to upthrust, the object

…………………… in the liquid

3. When weight is less than upthrust, the object …

in the liquid

floa

ri

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HAVE YOU ACHIEVE TODAY’SOBJECTIVE?

1. escribe what happens when ou stretch a s

%. /xplain what is mean b tension

&. /xplain the elastic limit

. /xplain wh things -oat or sin