Physics: Post your doubts here!

[hussamh10]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_21.pdf
Q2 c part how to determine what is the pivot to be taken
bamteck
TeKnOzOr
geek101

 

[caro24]

plz can someone help me..what are the experiments that i can be asked in exams for nuclear physics p2,,and how can i describe them plz plz ......i really need your help..god bless u

 

[geek101]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_21.pdf
Q2 c part how to determine what is the pivot to be taken
bamteck
TeKnOzOr
geek101

we are going to calculate moments about a point it can be any point, because the forces on A and B are unknown and the force on the midpoint (weight) is known. we will take moments around an unknown point, lets take A as the pivoting point >> to calculate the Force (tension) on B.

distance of the mid point from A = (1.5/2) - 0.3 = 0.45 m
distance of point B from A = 1.5 - 0.3 = 1.2
upward moments = downward moments
therefore, 0.45 x 2.4 = B x 1.2
B = 0.9 N

 

[TeKnOzOr]

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w11_qp_23.pdf
Q1 d part can any one show it how to do it in vector triangl way not mathematically....thanx plzzz
bamteck TeKnOzOr
geek101

Hehe dude...i always do it by the resolving forces methods..I actually didn't learn the vector methods..I tried to use ONLY one method for not confusing!!
Why don't you use the resolving method because its the easiest,according to me..!!
If yo don't know this method,just tell me i'll explain to you man..Don't worry

 

[hussamh10]

Hehe dude...i always do it by the resolving forces methods..I actually didn't learn the vector methods..I tried to use ONLY one method for not confusing!!
Why don't you use the resolving method because its the easiest,according to me..!!
If yo don't know this method,just tell me i'll explain to you man..Don't worry

no i know that method i was just curious as u know CIE can give anything so just wanted to learn that thanx any ways

 

[hussamh10]

we are going to calculate moments about a point it can be any point, because the forces on A and B are unknown and the force on the midpoint (weight) is known. we will take moments around an unknown point, lets take A as the pivoting point >> to calculate the Force (tension) on B.

distance of the mid point from A = (1.5/2) - 0.3 = 0.45 m
distance of point B from A = 1.5 - 0.3 = 1.2
upward moments = downward moments
therefore, 0.45 x 2.4 = B x 1.2
B = 0.9 N

Thanx alot so you are saying that we can takr the moment from any point???

 

[geek101]

Thanx alot so you are saying that we can takr the moment from any point???

now that you have got B, you can make B the pivoting point and calculate A..
1.2 x A = 0.75 x 2.4
A = 1.5 N
and this shows that the upward forces add up to 2.4 N. And proves that the rod is in equilibrium, and becuz of that you can take moments around any point.

 

[hussamh10]

now that you have got B, you can make B the pivoting point and calculate A..
1.2 x A = 0.75 x 2.4
A = 1.5 N
and this shows that the upward forces add up to 2.4 N. And proves that the rod is in equilibrium, and becuz of that you can take moments around any point.

Than alot now i get it by the way are u also giving in oct/nov??

 

[geek101]

Than alot now i get it by the way are u also giving in oct/nov??

no prob, yep

 

[hussamh10]

no prob, yep

Good Luck then !!

 

[TeKnOzOr]

no i know that method i was just curious as u know CIE can give anything so just wanted to learn that thanx any ways

Hehe man...yaa CIE is mad!! lol
But its IMPOSSIBLE that CIE ask for only the Vector method...Because never been the case before...
Unless the syllabus changes...lol So..relax

 

[hussamh10]

Hey plzz help me in how much sf must be the answer for eg http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_w11_qp_23.pdfin q3 ii)2 part
mgh=
1800 x 9.81 x 15=264870 how much s.f must be it taken and how to determine it???
geek101
TeKnOzOr

 

[TeKnOzOr]

Hey plzz help me in how much sf must be the answer for eg http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_w11_qp_23.pdfin q3 ii)2 part
mgh=
1800 x 9.81 x 15=264870 how much s.f must be it taken and how to determine it???
geek101
TeKnOzOr

Hmmm...for this,you must check the sf of the values given in the question itself..
for e.g, the tension = 3.1x10^4 N. You can see here that it is given to 2sf or 1dp
From this,it can be determined !!
Hope it helps!!

 

[hussamh10]

Hmmm...for this,you must check the sf of the values given in the question itself..
for e.g, the tension = 3.1x10^4 N. You can see here that it is given to 2sf or 1dp
From this,it can be determined !!
Hope it helps!!

1800 is 4 sf 9.81 is 3sf and 15 is 2sf so what we should do??

 

[geek101]

Hey plzz help me in how much sf must be the answer for eg http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_w11_qp_23.pdfin q3 ii)2 part
mgh=
1800 x 9.81 x 15=264870 how much s.f must be it taken and how to determine it???
geek101
TeKnOzOr

here are 3 rules
- when you are multiplying or dividing you round the value to the no. of sig figs of the least precise from the values used
- for addition and subtraction the no of decimal places in the result equals the number of decimal places in the least precise measurement
and they make sense cuz the answer cant be more precise than the values given
- if not specified then give answer to 3 sig figs

 

[hussamh10]

o

here are 3 rules
- when you are multiplying or dividing you round the value to the no. of sig figs of the least precise from the values used
- for addition and subtraction the no of decimal places in the result equals the number of decimal places in the least precise measurement
and they make sense cuz the answer cant be more precise than the values given
- if not specified then give answer to 3 sig figs

ok thank you

 

[axetreme.O]

My simple question is-" Can light apply force to something?" Kindly post your opinions..however facts are more welcome....

 

[Asheeta]

Hello, plz help for the sketch, I proportional to a^2
so how to calculate a of wave X? I'm stuck.
http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_w07_qp_2.pdf

 

[TeKnOzOr]

Hello, plz help for the sketch, I proportional to a^2
so how to calculate a of wave X? I'm stuck.
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w07_qp_2.pdf

Hii Asheeta...how are u..!?!​

okay remember that the 2 waves have the same frequency...so the wavelength remains the same, which is 30 boxes. you can use proportionality to do this. ​

If 15 boxes >> 180 degrees​

x boxes >> 60 degrees​

x = 5 boxes so that means, wave X is 5 boxes ahead of wave W​

​

now it says wave X has 1/2 the Intensity >> 1/4 the amplitude of W. ​

the amplitude of W >> 10 ​

10 x 1/4 = 2.5 ​

amplitude of X >> 10 - 2.5 = 7.5 boxes in the vertical direction​

​

​

Here is how the graph should look like...
Hope it helps

 

[Asheeta]

Hii Asheeta...how are u..!?!​

okay remember that the 2 waves have the same frequency...so the wavelength remains the same, which is 30 boxes. you can use proportionality to do this. ​

If 15 boxes >> 180 degrees​

x boxes >> 60 degrees​

x = 5 boxes so that means, wave X is 5 boxes ahead of wave W​

​

now it says wave X has 1/2 the Intensity >> 1/4 the amplitude of W. ​

the amplitude of W >> 10 ​

10 x 1/4 = 2.5 ​

amplitude of X >> 10 - 2.5 = 7.5 boxes in the vertical direction​

​

​

Here is how the graph should look like...
Hope it helps

ok thx