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Tuesday, January 26, 2010

SPM Physics: Unit Conversion

In responding to unit conversion questions posted by nina in the chat box, my advice is u need to polish your maths basic skills such as conversion & standard form. But in physics,..by now u shud already memorised the power of 10 for prefix like Mega, Giga, kilo, micro & etc.
For example:
Mega = M =
106
kilo = k =
103

Here some working examples of unit Conversion :
1. 5 kg = 5 (k)g
= 5 (
103 )g
= 5 x 103 g
( coz k is the prefix for
103, so just substitute the value of k with 103)


2. Lets change the unit from km/hr to m/s

7200 kmhr-2

= 7200 km / hr2


= 7200 x 103 m

-------- ----

( 60 x 60)2 s2


= 5.6 x 10 -1 ms-2


On next example i'll show u step by step how unit m3 is changed to cm3


4. 125 cm3, lets change the unit to m3


125 cm3 = 125( 1cm x 1cm x 1cm ), now we wanna change the unit cm to m,

coz prefix centi (c) means, c=10-2,so we subst symbol c with 10-2


= 125( 10-2m x 10-2m x 10-2m)


= 125( 10-2 x 10-2x 10-2) (m)3 see, the unit now changed to metre cube :)


= 125(10-2) m3


=125 x 10-6 m3


We can also rewrite it in standard form ,1.25 x 10-4 m3



If u still unclear with this conversion problems, u can email me at fizbro@gmail.com

1 comment:

  1. Thanks teacher! This was a great help as I am always confuse when converting the unit :)!

    ReplyDelete