24 hrs r up......full time analysis phyx P12

[Gooners]

Ahmmmm...........20-20000hz is just the AUDIBLE SOUND FREQUENCY .... Sound does have frequency above 20000 in case of bats........ 20-20000 is what we can hear ..... I was nt sure but did D that young modulus one as all the rest were correct ithink

 

[mrpaudel]

oh i remembered a question.....there was a question of couple in which resultant force shu b zero...whats the answer for that one?

 

[beststriker]

it was B...i thought there was a another ques for moment and i got answer 20 N which was option D for that one...was there any??

 

[libyafeb]

the one with the 0 resultant force for couples should be the one where the arrows are pointing in the opposite direction, along the same line like this
<----> because for resultant force to be 0 the distance between them needs to be 0 and the only one with the distance as 0 was i think option C

 

[MahirLatif]

oh i remembered a question.....there was a question of couple in which resultant force shu b zero...whats the answer for that one?

it was C .. Resultant force was zero

 

[mrpaudel]

it was B...i thought there was a another ques for moment and i got answer 20 N which was option D for that one...was there any??

yeah....20N was the answer for one question..!!

 

[MahirLatif]

it was B...i thought there was a another ques for moment and i got answer 20 N which was option D for that one...was there any??

yea the moment question was where bar was of weight 10 N and u had to find F which was balancing the bar about pivot X..
Answer was 10 N .. U selected 20 N (D) wrong..

 

[MahirLatif]

it was B...i thought there was a another ques for moment and i got answer 20 N which was option D for that one...was there any??

yeah....20N was the answer for one question..!!

not it wasnt :::::

 

[Zishi]

oh i remembered a question.....there was a question of couple in which resultant force shu b zero...whats the answer for that one?

it was C .. Resultant force was zero

No, it was B. Option number C wasn't showing a couple. Couple always tends to cause a rotation. With option number C, you could never cause the plank to rotate.

 

[MahirLatif]

Ahmmmm...........20-20000hz is just the AUDIBLE SOUND FREQUENCY .... Sound does have frequency above 20000 in case of bats........ 20-20000 is what we can hear ..... I was nt sure but did D that young modulus one as all the rest were correct ithink

yes.. But sound CANNOT have frequency that large.. If you do questions of young modulus.. Or just look up young modulus of some materials .. It falls well within that range... B, C and D were all possible..
A was the answer

 

[MahirLatif]

oh i remembered a question.....there was a question of couple in which resultant force shu b zero...whats the answer for that one?

it was C .. Resultant force was zero

No, it was B. Option number C wasn't showing a couple. Couple always tends to cause a rotation. With option number C, you could never cause the plank to rotate.

...
A had two forces acting downwards on each end... Moments = O . But resultant force not zero....

B had a force upward in the mid and one downward at one end..
C had two forces acting on same end but opposite..
What was D ?? And how is it B ? Care to explain ??

 

[mrpaudel]

i wrote D too..but in D..resultant force wont b zero i think..although it creates a rotation....

 

[EzioAuditre]

it was A for tht estimation one

 

[EzioAuditre]

for visible spectrum the frequency was ov order 15 not 14
as green lite has wavelength 570nm means 5.7*10-7 and hence frequency becums 15

 

[EzioAuditre]

i wrote D too..but in D..resultant force wont b zero i think..although it creates a rotation....

it was B

 

[grumpy]

i go with mahir.
sound with 10^9 thats too high yar.

 

[MahirLatif]

yea ,, cause then , keeping in mind reasonable speed, wavlength would have to be TOO small..
And anyways, the young modulus they stated was quite possible

 

[Gooners]

Hmmmmm.....anyways
the least uncertainity was surely D as all the instrumnts used fr D were the most precise from the options and greater the precision , less is the uncertainity......
As fr visible spectrum....
First use 4 x 10^-7= 3.0 x 10^8/4 x 10^-7
ur ansewer wd be 0.smethin x 10^15 which in fact is something x 10^14....
Thn do the same with 7x10-7 m wavelength...same result hence 10^14 is correct.....

Wat was the kinematics one ,was it 2v/gt?
Nd thn wat was answer to spring mattress one? I wrote B

 

[mrpaudel]

ok guys....for visible spectrum the answer is 10^14..now who got 10^15...jus think u lost other 1 mark too!!

 

[mrpaudel]

Hmmmmm.....anyways
the least uncertainity was surely D as all the instrumnts used fr D were the most precise from the options and greater the precision , less is the uncertainity......
As fr visible spectrum....
First use 4 x 10^-7= 3.0 x 10^8/4 x 10^-7
ur ansewer wd be 0.smethin x 10^15 which in fact is something x 10^14....
Thn do the same with 7x10-7 m wavelength...same result hence 10^14 is correct.....

Wat was the kinematics one ,was it 2v/gt?
Nd thn wat was answer to spring mattress one? I wrote B

yeah...kinematics one is D..but i wrote B..n for matress..its B!!