Author Topic: mechanics help  (Read 1365 times)

Offline manuroqs

  • Newbie
  • *
  • Posts: 13
  • Reputation: 5
mechanics help
« on: May 18, 2010, 05:28:57 pm »
hi! the mechanics ppr is tommorrow..Can anybody help me out with a question.It's from OCT/NOV 05 Q7)iii).How do u do it?

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: mechanics help
« Reply #1 on: May 18, 2010, 05:38:59 pm »
here

Offline manuroqs

  • Newbie
  • *
  • Posts: 13
  • Reputation: 5
Re: mechanics help
« Reply #2 on: May 18, 2010, 05:54:05 pm »
thanx :)
but the answer is wrong for the last part,it's 3.456 J in the marking scheme.I think u made a mistake in calculating the distance for ball with mass 0.3g

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: mechanics help
« Reply #3 on: May 18, 2010, 05:58:49 pm »
Check my working. Home again soon.

Offline Igcseboy

  • SF Citizen
  • ***
  • Posts: 183
  • Reputation: 191
Re: mechanics help
« Reply #4 on: May 18, 2010, 06:10:30 pm »
hi! the mechanics ppr is tommorrow..Can anybody help me out with a question.It's from OCT/NOV 05 Q7)iii).How do u do it?


which board???

Offline cooldude

  • SF Citizen
  • ***
  • Posts: 172
  • Reputation: 3600
Re: mechanics help
« Reply #5 on: May 18, 2010, 06:14:00 pm »
thanx :)
but the answer is wrong for the last part,it's 3.456 J in the marking scheme.I think u made a mistake in calculating the distance for ball with mass 0.3g

the height at which A is above the floor is-->
s=t(u+v)/2
s=1.2(0+2.4)/2
s=1.44m
B's final velocity-->
v^2=u^2+2as
v^2=2*2*1.44=2.4 m/s
dist travelled by B after string becomes slack until it comes to rest-->
v^2=u^2+2as
0=2.4^2+(2*-10*s)
s=0.288m
therefore total dist=0.228+1.44=1.728m
gain in gpe--> mgh=0.2*1.728*10=3.456 J

Offline zioziozio

  • The Silent Mind
  • Newbie
  • *
  • Posts: 28
  • Reputation: 42
  • Gender: Male
Re: mechanics help
« Reply #6 on: May 18, 2010, 06:25:23 pm »
hey guys .. can you please tell me the hardest mechanics paper u've solved before .. ?
because am revising and i need to know how the hard questions come .. Thanks :)
good luck to all !! :)
We can learn from the past .. But those days are gone .. We can look for the future .. But there may not be one ...

AL*Eagle

  • Guest
Re: mechanics help
« Reply #7 on: May 18, 2010, 08:56:27 pm »
hi! the mechanics ppr is tommorrow..Can anybody help me out with a question.It's from OCT/NOV 05 Q7)iii).How do u do it?

edexcel or cambridge??

Offline manuroqs

  • Newbie
  • *
  • Posts: 13
  • Reputation: 5
Re: mechanics help
« Reply #8 on: May 19, 2010, 08:14:36 am »
cambridge.But COOLDUDE solved it ;D