mechanics help

[manuroqs]

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?

[astarmathsandphysics]

here

[manuroqs]

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

[astarmathsandphysics]

Check my working. Home again soon.

[Igcseboy]

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???

[cooldude]

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

[zioziozio]

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 !!

[AL*Eagle]

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??

[manuroqs]

cambridge.But COOLDUDE solved it