Derived Quantities

A derived quantity is a Physics quantity that is not a base quantity. It is the quantities which derived from the base quantities through multiplying and/or dividing them.
Example

(Speed is derived from dividing distance by time.)

Derived Unit
The derived unit is a combination of base units through multiplying and/or dividing them.
Example 1
Find the derived unit of density.
Answer
Unit Conversion
Area and Volume
Example 2
Convert the unit of length, area and volume below to the units given.
a) 7.2 m = ____________cm
b) 0.32 m2 = ____________cm2c) 0.0012 m3 = ____________cm3d) 5.6 cm = ____________m
e) 350 cm2 = ____________m2f) 45000 cm3 = ____________m3Answer
a) 7.2 m = 7.2 x 102 cm
b) 0.32 m2 = 0.32 x 104 cm2 = 3.2 x 103 cm2
c) 0.0012 m3 = 0.0012 x 106 cm3 = 1.2 x 103 cm3
d) 5.6 cm = 5.6 x 10-2 m
e) 350 cm2 = 350 x 10-4 m2 = 3.5 x 10-2 m2
f) 45000 cm3 = 45000 x 10-6 m3 = 4.5 x 10-2 m3


Speed
Example 3
Complete the following unit conversion
a) 12 kmh
-1 = __________ ms-1
b) 12 ms
-1 = __________ kmh-1

Answer


a) \[\begin{array}{l} 12km{h^{ - 1}}\\ = \frac{{12km}}{{1h}}\\ = \frac{{12000m}}{{60 \times 60s}}\\ = 3.33m{s^{ - 1}} \end{array}\]

b)
\[\begin{array}{l} 12m{s^{ - 1}}\\ = \frac{{12m}}{{1s}}\\ = \frac{{\frac{{12}}{{1000}}km}}{{\frac{1}{{3600}}h}}\\ = 43.2km{h^{ - 1}} \end{array}\]

17 comments

  1. Ä‚anniiss // March 10, 2009 at 8:54 AM  

    Now i know how to answer questions like this ! Thank you so much!

  2. jackiez // May 14, 2009 at 1:13 AM  

    thankyou u so much!
    i am facing my physic test on tomorrow...lucky i view your website...it helps me a lot!

  3. Mengapa ? // May 14, 2009 at 9:01 AM  

    lolz..im havin my test on friday

    this site is vry good ^^

  4. ae_tone // May 15, 2009 at 1:58 AM  

    hey i just knew about dis website.
    its very good.
    i'm havin my exam next week...
    it helps me a lot
    thank you
    thanx
    tq
    ???!!!

  5. sfnh // June 20, 2009 at 9:05 PM  

    hey, found your blog last week.

    im very very weak in physic and your web is helping me to get better marks for physic in SPM.

    thanks a lot :D

  6. mary // August 29, 2009 at 6:31 AM  

    thanks a lot 4 all the notes....the notes are really helpful...=)

  7. moonboy126 // December 1, 2009 at 7:48 AM  

    Hey! after PMR exam is over, I get prepare and study Science Form 4... But why the chapter 1 is easy as shit!?!? OMG...

  8. www.ashivinbast // February 10, 2010 at 9:08 PM  

    thank for it, now i can understand it so much

  9. www.ashivinbast // February 10, 2010 at 9:10 PM  
    This comment has been removed by the author.
  10. shasha // March 1, 2010 at 2:51 AM  

    i am sitting 4 my physics test tomorrow~ luckily i found this site!! it helps me a lot!! thanx~

  11. qaseh sakura // April 29, 2011 at 4:18 AM  

    =.=" physics!!! ....

  12. Hui // May 19, 2011 at 8:27 PM  

    its good

  13. Hui // May 19, 2011 at 8:28 PM  

    it's a good note

  14. umair awan // January 30, 2012 at 7:06 AM  

    themicavery helpfull

    hhrteiwgvdfnfjjf dydf fygf guydf ygrdyewgfd dygwed yegwyfdug dyewgdyu

  15. kuhan muruga // February 12, 2013 at 5:42 AM  

    thank you very nuch for this working.hope will have same blog for all subjects.thank you :)

  16. Ian Khoo // September 17, 2013 at 8:46 AM  

    sorry but my physics and maths are very poor. i dont understand and do not know how to do the questions. could you show more detailed working methods?

  17. glamour with ada marcella OFFCIAL // November 11, 2013 at 7:59 AM  

    Thanks for the notes. I'm not a pure science student but I'm interested in the subject of physics because I want to be an aircraft engineer.