Author Topic: The Exam Defied The Laws Of Mechanics.  (Read 2156 times)

Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
The Exam Defied The Laws Of Mechanics.
« on: May 20, 2010, 08:43:14 am »
guys in mechanics paper 42, the coefficient of friction was 1.62 right?

you cant possibly get a coefficient greater than 1 :S

Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

Offline islu_jf

  • Newbie
  • *
  • Posts: 30
  • Reputation: 16
  • Gender: Female
  • I-GEAR IS THE BEST OF THE BEST
Re: The Exam Defied The Laws Of Mechanics.
« Reply #1 on: May 20, 2010, 08:47:21 am »
hey i got the same number 2/... i was going to change it.. bt NO TIME>!!

Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
Re: The Exam Defied The Laws Of Mechanics.
« Reply #2 on: May 20, 2010, 08:54:05 am »
no it is im 100% sure, but theoretically its wronnggg :S
Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

nid404

  • Guest
Re: The Exam Defied The Laws Of Mechanics.
« Reply #3 on: May 20, 2010, 09:12:10 am »
no it's not....where did you read that co-eff of friction can't be greater than 1...it can very well be


Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
Re: The Exam Defied The Laws Of Mechanics.
« Reply #4 on: May 20, 2010, 09:17:59 am »
only 2 percent of all materials on earth have a coefficient of friction greater than one! and plus, not in the book or in any paper was there a coefficient greater than one! it was pissing off, i wasted time revising the question a million times! but thank god the rest was dead easy :)
Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

nid404

  • Guest
Re: The Exam Defied The Laws Of Mechanics.
« Reply #5 on: May 20, 2010, 09:21:14 am »
a value above 1 merely implies that the force required to slide an object along the surface is greater than the normal force of the surface on the object.

stop bothering  :P

Offline islu_jf

  • Newbie
  • *
  • Posts: 30
  • Reputation: 16
  • Gender: Female
  • I-GEAR IS THE BEST OF THE BEST
Re: The Exam Defied The Laws Of Mechanics.
« Reply #6 on: May 20, 2010, 09:22:08 am »
What did u gt for Question 5 part (ii) ??
it was about the mgh and work done against friction???
what was the hight?

Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
Re: The Exam Defied The Laws Of Mechanics.
« Reply #7 on: May 20, 2010, 09:22:36 am »
hahaha okay okay im sorry :P
Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
Re: The Exam Defied The Laws Of Mechanics.
« Reply #8 on: May 20, 2010, 09:23:15 am »
What did u gt for Question 5 part (ii) ??
it was about the mgh and work done against friction???
what was the hight?

part i) the velocity was 3

and the height was 0.32 m
Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

Offline XaM!!

  • SF Master
  • ******
  • Posts: 1637
  • Reputation: 2680
  • Gender: Male
Re: The Exam Defied The Laws Of Mechanics.
« Reply #9 on: May 20, 2010, 09:23:17 am »
i ****ed 1 part... i couldnt prove v=3.95... because of no time...
Dnt walk As iF u RulE da WorLd..... Walk As if U dOnT CarE wHO RuLzz It.......



nid404

  • Guest
Re: The Exam Defied The Laws Of Mechanics.
« Reply #10 on: May 20, 2010, 09:24:47 am »
part i) the velocity was 3

and the height was 0.32 m

yup :)

Offline islu_jf

  • Newbie
  • *
  • Posts: 30
  • Reputation: 16
  • Gender: Female
  • I-GEAR IS THE BEST OF THE BEST
Re: The Exam Defied The Laws Of Mechanics.
« Reply #11 on: May 20, 2010, 09:33:11 am »
Ohh...  i got the hight as 0.13 and then the mgh is 0.31!! which is the same as the WD against frictional force!!!!!
i ddnt do gd in the last question.. no time man..
it was Ok .. bt very long//

Offline [Spy]

  • SF Joker (2)
  • SF Geek
  • ****
  • Posts: 532
  • Reputation: 750
  • Gender: Male
  • Watch Your Back.
Re: The Exam Defied The Laws Of Mechanics.
« Reply #12 on: May 20, 2010, 09:49:26 am »
:)


don't worry, you'll do good :)
Kids in back seats cause accidents, accidents in back seats cause kids.
David Guetta<3
Student Forum<3

Offline SAKS10111

  • Newbie
  • *
  • Posts: 29
  • Reputation: 29
Re: The Exam Defied The Laws Of Mechanics.
« Reply #13 on: May 20, 2010, 10:37:37 am »
i also got the co-eff as 1.62, and i know its right, because it wasn't even a very complicated question. hope its right
in the 5th question, instead of taking the height as .45 m, i took it as 45 m :( my working and method is totally right, but my figures are obviously wrong, do you think i'd get some consideration marks for that? that was 7 marks, the rest of the paper i think i did pretty good.
what was your last answer, the speed/velocity? i got 5.4 i think

Offline @ce/AJ

  • Newbie
  • *
  • Posts: 18
  • Reputation: 11
Re: The Exam Defied The Laws Of Mechanics.
« Reply #14 on: May 20, 2010, 10:38:43 am »
I was getting something above 1 as well so I'm like this isn't possible and changed my answer to 0.6.
Tht's 3 marks gone!  :'(