Mechanics Paper 42 Solutions

[[Spy]]

guys here are the solutions for the whole paper and im very sure of them

1) a=0.845

2) i) 0.09
    ii) 1.08
    iii) 0.72

3) i) 3.05
    ii) 1.62

4) 500N 38.9 to the x-direction

5) i) 3
    ii) 0.32

6) i) a=6 & v=3.95
    ii) i did a silly mistake here so i dont know the right answer. someone post it

7) i) A=4 & B=3375
    ii) -3375/t + k (though i did a silly mistake here i forgot to put K, GODDD!!! :@) so i dont know the value of K
    ii) DO YOU GUYS THINK I'D GET AN ECF? answer was something around 5.4

[XaM!!]

ur ans r same as mine... BUH I ****ed one part.. my acc came 6 but V wasnt coming 3.95. wat do u thnk how many marks will deduct??? it was of 7 marks... i got acc 6..

n my B was coming in negative... -377smthn...

[neno]

how many marks was 5 ii) worth....how r u sure these r the ryt answers....i got all the same answers other than this part sumhow i got 0.13 as the height
dont u do 1.35-workdone against resistance=ke-pe
then PE =0.39 i think i dont remember
 

[panther]

For question 4 it was 36.9 to the x-direction

[neno]

For question 4 it was 36.9 to the x-direction

yea i think i got tht 2 cant remember the figures tht well

[XaM!!]

how many marks was 5 ii) worth....how r u sure these r the ryt answers....i got all the same answers other than this part sumhow i got 0.13 as the height
dont u do 1.35-workdone against resistance=ke-pe
then PE =0.39 i think i dont remember
 

ya

P.E = K.E + (W.D)resistance...


evn i forgot my ans... but m sure they r rite... I MESSED THAT VELOCITY=3.95 PART!!! It was of 7 marks... m feeling HORRIBLE!!!

[cockyxrocker]

for question 7(ii) didnt they ask you for the total distance travelled and not the displacement?...
i got k as zero and my expression was 225 + 3375/t
and i got 2.4 for 7(iii)

[[Spy]]

yeah im sorry it was 36.9

and yeah im sure of the rest

i hope i dont loose much due to silly mistakes :S

[[Spy]]

how many marks was 5 ii) worth....how r u sure these r the ryt answers....i got all the same answers other than this part sumhow i got 0.13 as the height
dont u do 1.35-workdone against resistance=ke-pe
then PE =0.39 i think i dont remember
 

someone remind me of the particle's mass :S

[cashem'up]

yea i got the same answers whereas in
6 ii i got i think 3.29 because now the particle will be decelartng against friction
and for 7 ii i got k as 450
and the next part v as 5.4....yep just reassure 6 ii otherwise i m sure this is rite.....

[[Spy]]

yeah i did it wrong because i forgot to remove tension! GOD!! :S

but yeah k was something like that =D

[vserian]

hey for the 3rd question

i got the coefficient as 1.62 but coefficient of friction is not suppose to be more than 1!
i think they made an error with the qustion, i wrote 0.62 insted of 1.62

overall it was a ok paper!

[[Spy]]

no its not impossible to have a coefficient more than 1 but its very rare! like for all the years is always less than one and not many meterials on earth have a coefficient more than 1

but it is perfectly fine and its 1.62

[cashem'up]

no its not impossible to have a coefficient more than 1 but its very rare! like for all the years is always less than one and not many meterials on earth have a coefficient more than 1

but it is perfectly fine and its 1.62

yea exaclty its like on average practically it might not even be possible bt theoretically....its diferent

[vserian]

yea exaclty its like on average practically it might not even be possible bt theoretically....its diferent

Well every question i did about coefficients, the answer is below 1 and even theoretically its wrong
all my teaches said it shuld be under 1 and i think CIE did mistake with the paper cause if the tension in the strig is less than the weight then practically it cant move so there wont move so friction is more then the force that agaist the friction and if the cooeffficent of firction is more then 1 then friction will make objects move! thats impossible!