PHYSICS PAPER 4 (ATP) DISSCUSSION

[Abhiyash]

but for (4)
i've written the opposite of ur answer...
u've said time decreases...and i've said that time increases and i've mentioned that the rule may hardly rotate or does not rotate smoothly when d is less than 15cm..

 

[Shiki Misaki]

i've mentioned that the rule may hardly rotate or does not rotate smoothly when d is less than 15cm..

Yeah, when time increases, distance decreases. Or vice-versa.
And for d<15, your answer is good but it demands more elaboration. You could have said that there would have been an error in determining the time taken for one rotation.

 

[Abhiyash]

was it only for 1 mark? or 2?

 

[Shiki Misaki]

I guess, 1 mark.

 

[Abhiyash]

Good...and yeah did u use stopwatch or wallclock??and wat reason did u mention?

 

[Shiki Misaki]

A stopwatch since the readings are more accurate and no human reaction time error can occur compared to the clock.

Edit>> How about your answer?

 

[Abhiyash]

Same...for better accuracy and the experiment could be conducted conveniently...
this part also was for 1 mark...rite?

 

[Shiki Misaki]

Yeah.

 

[Prince III]

when the d < 15 then the T would be tooo LARGE not tooo small , that there might be human reaction error while calculating the T



and for how to check d=d
we have to measure the distance from 50 cm mark on ruler A (which was centre of gravity) to the place where the string is connected and make sure for both string length is same
or any other statement which show that we have to take distance from 50cm mark (centre of gravity )
so Shiki Misaki your answers is wrong for the above two

for the quetion: show that d and T were inversly proportinal
Abhiyash d x T would give us constant value that would just show that they are in proportional but the question stated to show that they are INVERSLY PROPORTIONAL !




SEE the below diagram for the eye question

 

[rose1700]

for the question show d and T are inversly proportioal i just wrote

" when d is incereasing then , T is decreasing "



How many marks would be granted

 

[Shiki Misaki]

@ Prince III: To check whether both strings are of the same distance, in my answer I stated that the readings are taken from the centre and that both the readings of the metre rules should be the same. So i won't be penalized for this.

Secondly, when d<15, the clamps will oscillate with a smaller force, therefore resulting in a greater time(for one oscillation), true! But I have also stated that there would be a greater percentage error. I may be given half of the mark, no? :S

Edit>> Hey I'm so confused right now.
If d>15cm, the time taken for the set of rotations(20) would have been greater than the time taken for another set of rotations(9) when d<15cm, innit? Please confirm.

2nd edit>> How come the eye is placed above the clamp? :S
The eye shouldn't be placed perpendicular to the clamp by the way?! (to avoid parallax error when recording the number of rotations)

 

[Depletion]

A stopwatch since the readings are more accurate and no human reaction time error can occur compared to the clock.

Edit>> How about your answer?

heyyyy...
for the stopwatch and the wallclock...!!
i guess its the wallclock...
because it is said that the stopwatch can only measure 0.01s and the experiment require 1 min...
the stopwatch can only measure 9s???

plz disscusss abt that question !!!???

 

[bamteck]

Yea we need to reset the stopwatch everytime!!

 

[Depletion]

yepss..!!!)

 

[Shiki Misaki]

heyyyy...
for the stopwatch and the wallclock...!!
i guess its the wallclock...
because it is said that the stopwatch can only measure 0.01s and the experiment require 1 min...
the stopwatch can only measure 9s???

plz disscusss abt that question !!!???

Who said that the stopwatch can measure only up to 9s ???? And besides, the stopwatch starts measuring as from 0.01s and not "the stopwatch can only measure 0.01s"

 

[maths maldives]

heyyyy...
for the stopwatch and the wallclock...!!
i guess its the wallclock...
because it is said that the stopwatch can only measure 0.01s and the experiment require 1 min...
the stopwatch can only measure 9s???

plz disscusss abt that question !!!???

Who said that the stopwatch can measure only up to 9s ???? And besides, the stopwatch starts measuring as from 0.01s and not "the stopwatch can only measure 0.01s"

stopwatch can measure time for only 60s!

 

[Shiki Misaki]

And 60 seconds is equal to 1 minute. So if the experiment is for about 1 minute, there can be nothing better than using a stopwatch.

 

[Prince III]

@ Prince III: To check whether both strings are of the same distance, in my answer I stated that the readings are taken from the centre and that both the readings of the metre rules should be the same. So i won't be penalized for this.

ohh, if you have stated centre then you wont

Secondly, when d<15, the clamps will oscillate with a smaller force, therefore resulting in a greater time(for one oscillation), true! But I have also stated that there would be a greater percentage error. I may be given half of the mark, no? :S

yes you might be half credited

>> Hey I'm so confused right now.
If d>15cm, the time taken for the set of rotations(20) would have been greater than the time taken for another set of rotations(9) when d<15cm, innit? Please confirm.

yes

2nd edit>> How come the eye is placed above the clamp? :S
The eye shouldn't be placed perpendicular to the clamp by the way?! (to avoid parallax error when recording the number of rotations)

No! not at all
it should be above
did you see the third diagram >?
fig . 1.3

that was the picture if we put our eye on the top



FOR THE STOPWATCH QUESTION
guys we have to use stopwatch (CONFIRM)

first of all there was nothing written in question that the experiment requires more than 1 minutes okay !
and most of the stpwatches measure 60 seconds
more over " 0.01" this does not shows that the stopwatch can only measure 1 minutes , this shows how accurate the stopwatch is , stpwatch can give upto 2 decimal place value (very very very accurate )

secondly i can prove that the experiment wont take more than 1 minute
the minimum d we could take was 15cm below that we can not take as written in another question
the time for 1 oscilation when d= 15 was 2.74s

now even if we take maximum oscillations =20

2.74 x 20 = 54.8 seconds (less than 1 minute )

So the experiment wont require more than 1 minute

HOPE everyone got that!

this was the easiest question
moreover stopwatch would give us better control over time to measure (we could easily record the value and then reset it )
how coulds we rset wall clock ?

and i have never seen someone calculating oscilations with wall clock
seems stupid infact

 

[Shiki Misaki]

>> Hey I'm so confused right now.
If d>15cm, the time taken for the set of rotations(20) would have been greater than the time taken for another set of rotations(9) when d<15cm, innit? Please confirm

That's what i was trying to say. I think if i would have included a 's' in my answer, i would have got the full mark. :/.

2nd edit>> How come the eye is placed above the clamp? :S
The eye shouldn't be placed perpendicular to the clamp by the way?! (to avoid parallax error when recording the number of rotations)

No! not at all
it should be above
did you see the third diagram >?
fig . 1.3

that was the picture if we put our eye on the top

Uhhh, you're sure? The fig 1.3 was not from the front?.. or was it stated in the paper that the image is from above? :S :S I still support my answer.

 

[Prince III]

dude while attempting the paper i knew most of the people would get this wrong

where figure 1.3 was drawn below that it was written

FIG. 1.3 ( from the top view )


in brackets it was written from the top view