mechanics 18th/oct 2010 discussion

[Islu_jf]

Hey are u guys finished with it?

 

[ASTAR]

it was hard , but we can not talk about the exam now wait 24 hr

 

[oneluckynumber]

YES! finished a few hours ago Mechanics 42- dint think it was too complicated ! assessable which obviously means high averages and really minor careless mistakes of 2-3 points will decide between A or B !

 

[Shafaque]

Q4 and last one was confusing
paper was tricky though

 

[grimreaper_123]

mann...ppr was very tricky!! :c
dun know wat ill get

 

[usamazee]

paper went well but was really tricky and lengthy compared to the time given.question 5 part 2 was the trickiest one that i found.

 

[Frooty]

paper was tricky at Q5)b) and Q7
m still hittin my head . had 20 mins left fo Q7. still managed to do nothing. did'nt know where to start from :S
please post the answers to Q5)b) just as the 24hr barrier ends

 

[MAVtKnmJ]

This is still called discussing, kindly refrain from discussing even the difficulty level of the questions until a few more hours.

Thanks!

 

[Frooty]

overviewing the complete paper. what will be the estimated percentile ?

 

[MAVtKnmJ]

Try your best to score an A in Mechanics as well because you never know how high the percentile/percentage for an A will be. I say that because usually in P1 an A is 63-65 and in M1 it is 43-46.

Best of luck!

 

[Frooty]

63-65 is ok with p1.
but this time percentie for m1 should be fairly low because whenever there has been a tough paper. '' A '' has been given on 36-40 !! it has happened 3 times earlier.

 

[cyberoxis]

Can we discuss now .... especially question 5....

 

[cyberoxis]

okay 24 hours done....

question 5

A particle P is released vertically upwards with initial speed 20 and 0.4 seconds later a particle Q is released with speed 25. find
(i)the time P remains above 15 meters
(ii) the velocity of P and Q when they are at the same height....

 

[cyberoxis]

how many marks were each part .... how many marks do you get in part two if you add 7.2 to the displacement function but forgot to change the initial speed of P from 20 to 18....

 

[ubhek]

hey guys n grls...is the 24 hr time barrier from the starting tym of the paper or the end,,,

 

[adzino]

Ok i dont remember much but i am trying my best to recall..
Question 1
force around 2000N acting 15 to the vertical upwards.
object of mass 400kg.
the object is in limiting equilibrium
find the coffecient of friction

question 2
something about work power energy i dont remember

question 3(was tricky for me)
i guess the angle was 83-84 degree...force i dont remeber

question 4
this also i dont remember much probably work power energy

question 5
particle P and Q question. part ii was a bit confusing i missed 5 marks over here cuz i didnt get the time to solve

question 6

graph question
velocity i guess V=6
t=8.5s
others i dont remeber

question 7.

t1=10, t2=30
distance is 285 m (i dont remebr exectly)

and what else...i can remember upto this much

 

[ubhek]

5i) s=ut +1/2 at^2....s=15, u=20, then comes quadratic eqn for t ..t=3 and 1...final ans is t=3-1=2sec..
ii)for p...s1=20t -5t^2.....for q...s2=25(t-0.4)-5(t-0.4)^2... s1=s2....t=1.2 sec...
V(p)=20-10*1.2=8m/s V(q)=25-10*(1.2-0.4)=17m/s...



can any one remind me how the figure of question 6 was...lower triangle from 0-2.5 then i don't remember...
and question 4 too

 

[ubhek]

Ok i dont remember much but i am trying my best to recall..
Question 1
force around 2000N acting 15 to the vertical upwards.
object of mass 400kg.
the object is in limiting equilibrium
find the coffecient of friction

question 2
something about work power energy i dont remember

question 3(was tricky for me)
i guess the angle was 83-84 degree...force i dont remeber

question 4
this also i dont remember much probably work power energy

question 5
particle P and Q question. part ii was a bit confusing i missed 5 marks over here cuz i didnt get the time to solve

question 6

graph question
velocity i guess V=6
t=8.5s
others i dont remeber

question 7.

t1=10, t2=30
distance is 285 m (i dont remebr exectly)

and what else...i can remember upto this much

ans 1 was 0.25...ans 3 F=5.52.....hey...can you remind me how the figure of question 6 actually was..

 

[Frooty]

Q5)b)
s=ut + 1/2 at^2 write the equations of ""s"" for both particles and equal them

but the tricky part was tht q had started 0.4s later than p

so i managed to find the distance travelled by p for the 0.4s
it was 7.2m .. then altered the equations

solved the equations and got t=1.44s where t is the time where both particles are at same height
using formula v=u+at
i got velocity of p = 5.6 m/s
q = 10.6 m/s

is it correct?

 

[Frooty]

and share ur views about Q7
was difficult for u? i left the whole question.did'nt know where to start from :s