Physics p34 05 june 2014

[comrade]

in q1 we have to note time for 10 ocsillations per value, right??

I have no idea at the moment. I myself am scrolling through stuff looking for a similar experiment. I'll mention it here if something new pops up.

 

[Jelleh Belleh]

in q1 we have to note time for 10 ocsillations per value, right??

To find time taken for one oscillation: Record time taken for 10 oscillations twice (2 trials), take the average of both readings then divide the average by 10.
You don't always use time taken for 10 oscillations though, sometimes the oscillations are very small, making it impossible to count 10.

 

[ddude94]

Finally I got something- The chances that this will come is at 90%.

Guess for phy practical.

Q1: pendulum experiment. We will be provided with a S shape hook. We would hang this hook to some support. We would have a V shape wire which we will hang /\ this way with the S shape hook. At the end of the wire we would hang different weights and measure the time for oscillation, make graph and calculate gradient and y-intercept and similar stuff.

Q2: we would be provided a ball and a ramp along with a meter rule and and stop watch. We have to measure time for the ball to reach the end of the inclined plain.

Not sure how much of this is true but this is the most I got. Hope it helps.

thanks for this.
can someone state the limitations and improvements that we can write from the information available for Q2? i'd highly appreciate it.
thanks

 

[Mustafa Malik]

thanks for this.
can someone state the limitations and improvements that we can write from the information available for Q2? i'd highly appreciate it.
thanks

Two sets of readings not enough............ If it's a ball then force has to be applied to push it so improvement is yes a mechanical method to push the ball. If they say to measure time or any other quantity to prove a relation then u can say that uncertainity in time is greater so use a larger ramp . This will give u a greater t n uncertainity will be less. Ramp is not smooth and different sides of the ramp hv different friction so mark the section of ramp used in exp 1 n then use the same side again cuz friction will be same so it won't affect . All I know

 

[Jelleh Belleh]

thanks for this.
can someone state the limitations and improvements that we can write from the information available for Q2? i'd highly appreciate it.
thanks

Question 2 of the oct/nov 2012 paper 34 looks to be extremely similar to what we might get, based on what comrade said. Read the limitations & improvements from it's marking scheme.

 

[dumb human]

I have no idea at the moment. I myself am scrolling through stuff looking for a similar experiment. I'll mention it here if something new pops up.

If they ask us to Justify the number of significant figures...what should we exactly say?

 

[dumb human]

Question 2 of the oct/nov 2012 paper 34 looks to be extremely similar to what we might get, based on what comrade said. Read the limitations & improvements from it's marking scheme.

And If they ask us to Justify the number of significant figures...what should we exactly say?

 

[ZaqZainab]

Aray yar.He was talking about the relationship for example X=kT^2.
So they ask us to find the two values of k first and then whether our results justify the relationship.So we find the %error
%error = diffrence between the two values of k/average of the two values of k multiplied by 100.If its less than 10 then its justified otherwise not.

i just checked the text book it says diffrence between the two values of k/smallest value of the two values of k multiplied by 100

 

[comrade]

thanks for this.
can someone state the limitations and improvements that we can write from the information available for Q2? i'd highly appreciate it.
thanks

For the exact answer see this link. Q2, part h.

Question 2 of the oct/nov 2012 paper 34 looks to be extremely similar to what we might get, based on what comrade said. Read the limitations & improvements from it's marking scheme.

Please don't rely on what I said. I'm just trying to help out. That aside, the paper you mentioned is the first one I practised.

And If they ask us to Justify the number of significant figures...what should we exactly say?

It depends on the instrument you are using. For example a balance that measures mass of an object shows 2.5 g so it is 2 significant number. You can't write it as 2.50 g. That would be wrong. Another example is the metre rule. You get a measurement of 10.5 cm so you cannot write it as 10.50 cm as it will ruin the precision and will make it inaccurate. A metre rule or a ruler can't measure more than that. I hope you understand what I am trying to say.

 

[comrade]

i just checked the text book it says diffrence between the two values of k/smallest value of the two values of k multiplied by 100

I read exactly the same. But many people are now saying that we have to take the average. I don't know which one is correct. :/ I asked from a A* student, I was told that I have to take an average. Still not sure.

 

[ZaqZainab]

I read exactly the same. But many people are now saying that we have to take the average. I don't know which one is correct. :/ I asked from a A* student, I was told that I have to take an average. Still not sure.

but did you ask them that why does the course book take the smallest value?

 

[comrade]

but did you ask them that why does the course book take the smallest value?

I asked through someone, not directly. I did ask but was given only this much reply.

 

[dumb human]

For the exact answer see this link. Q2, part h.



Please don't rely on what I said. I'm just trying to help out. That aside, the paper you mentioned is the first one I practised.



It depends on the instrument you are using. For example a balance that measures mass of an object shows 2.5 g so it is 2 significant number. You can't write it as 2.50 g. That would be wrong. Another example is the metre rule. You get a measurement of 10.5 cm so you cannot write it as 10.50 cm as it will ruin the precision and will make it inaccurate. A metre rule or a ruler can't measure more than that. I hope you understand what I am trying to say.

ohhhhh i get you! thankx a lot =D

 

[MYLORD]

Its for inclined planes

 

[MYLORD]

ohhhhh i get you! thankx a lot =D

Can u tell me that this incline plane thingy , is it related to momentum topic somehow ??

 

[dumb human]

Can u tell me that this incline plane thingy , is it related to momentum topic somehow ??

Its like we will have to time the ball , with distance.....rolling all the way down till it stops.
And take average values for time and distance.
and correct units =D

 

[talha-_-khan]

to find percentage value do this 100% sure
{ [ ( largest_value - Smallest_value ) / 2 ] / [ ( average_value ) ] } x 100 = percentage uncertainty
eg we have d1 = 6.8 and d2 = 6.9
percentage uncertainty = { [ ( 6.9 - 6.8 ) / 2 ] / [ ( 6.9 + 6.8 ) / 2 ] } x 100 = 0.72 %

FOR K VALUES DO THIS
find 1 percent of bigger k value and minus that from the bigger value or add it to small value and check if they lay within 1 percent of each other

 

[comrade]

Can u tell me that this incline plane thingy , is it related to momentum topic somehow ??

See O/N 12, P34, Q2. It is almost the same.

to find percentage value do this 100% sure
{ [ ( largest_value - Smallest_value ) / 2 ] / [ ( average_value ) ] } x 100 = percentage uncertainty
eg we have d1 = 6.8 and d2 = 6.9
percentage uncertainty = { [ ( 6.9 - 6.8 ) / 2 ] / [ ( 6.9 + 6.8 ) / 2 ] } x 100 = 0.72 %

This is what I was told, is this wrong or the same thing?
K2-K1
----------------- x100%
K1+K2
-----------
2

 

[dumb human]

to find percentage value do this 100% sure
{ [ ( largest_value - Smallest_value ) / 2 ] / [ ( average_value ) ] } x 100 = percentage uncertainty
eg we have d1 = 6.8 and d2 = 6.9
percentage uncertainty = { [ ( 6.9 - 6.8 ) / 2 ] / [ ( 6.9 + 6.8 ) / 2 ] } x 100 = 0.72 %

FOR K VALUES DO THIS
find 1 percent of bigger k value and minus that from the bigger value or add it to small value and check if they lay within 1 percent of each other

Thankx a looooooooooooooot =D

 

[talha-_-khan]

See O/N 12, P34, Q2. It is almost the same.



This is what I was told, is this wrong or the same thing?
K2-K1
----------------- x100%
K1+K2
-----------
2

For k the method is to find whether the 2 values lay within 1 percent of each other and as for % unc is concerned and according to ur values its{ [ ( K2-k1 ) / 2 ] / ( avg val ) } x 100 but this is for percentage uncertainty not for K ( constant )