Physics: Post your doubts here!

[mynameisjh]

Guys need help with this question S13 9702 13

19) A model is made of the crane, its load and the cable supporting the load.
The material used for each part of the model is the same as that in the full-size crane, cable and
load. The model is one tenth full-size in all linear dimensions.
What is the ratio
extension of the cable on the model crane/extension of the cable on the full-size crane ?


A 100 B 101 C 102 D 103
Answer is C but why?? (p/s there is a diagram but i do not know how to include it in here sorry but i dont think it's really important)

 

[Khadija_1234]

What is the absolute uncertainty of a meter when we perform experiments in practicals?

 

[Khadija_1234]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_1.pdf
Need help with Q6 please

 

[Jessie N.]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_1.pdf
Need help with Q6 please

XD

 

[Jessie N.]

SOMEONE HELP PLS!!!
A projectile leaves the ground at an angle of 60 to the horizontal. Its initial kinetic energy is E. Neglecting air resistance, find in terms of E its kinetic energy at the highest point of motion.

Just trying, not sure the answer is correct or not 0.0

 

[Jessie N.]

Guys need help with this question S13 9702 13

19) A model is made of the crane, its load and the cable supporting the load.
The material used for each part of the model is the same as that in the full-size crane, cable and
load. The model is one tenth full-size in all linear dimensions.
What is the ratio
extension of the cable on the model crane/extension of the cable on the full-size crane ?


A 100 B 101 C 102 D 103
Answer is C but why?? (p/s there is a diagram but i do not know how to include it in here sorry but i dont think it's really important)

You type the question wrongly XD, should be extension of the cable on the full-size crane/extension of the cable on the model crane

I can manage to find the answer but I think my method is quite complicated, I find the ratio of stress before finding the ratio of extension (coz we don't know how much force is used)
I wonder maybe there is another easier way to do it, by the way you can just take my solution as a reference )))

 

[smoothieoeek]

I think for question 11,the for both has same reaction force as the weight for the both objets r same.While for the tension thing, I am not sure.Hope someone else here give a hand.
For the second question,some one else explanation ---- first... since applied force is constant, the torque (F*d) will be proportional to d.... torque for 100mm is 3.. so for 150mm , it will be 4.5Nm... so we have to look for the tensions now..torque is the product of force and moment arm.. and the only force present here is the tension in the belt so 3=F*.1 F=30N
for the other wheel, 4.5=F*.15 F=30... so total force is equal to 30N to 30N = 60N...

Ok i get the second question now. Thanks!

 

[Jessie N.]

Heeeelp plzzz！！(´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`)

 

[periyasamy]

Heeeelp plzzz！！(´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`) (´•̥̥̥ω•̥̥̥`)

Ok no problemo.For the question no33,i think it a bit logically.Path B shows path taken by proton.So now for helium nucleus it is
4 1
2 he 1 p.
------------>the helium is much heavier than the proton.....So,it would need a greater distance to be completely deflected than
the proton..For the direction,it should be same as the proton as both r same charge.

For the second question mean power dissipated is done by calculating the= highest power+lowest power/2
Highest power=i^2*r==>2^2*100=400 watt
lowest power=-1^2*100=100watt
400+100/2=250 watt

For the third question,,
option a rite-----Because when the s1 is closed,althugh s2 is also closed,the current will instead pass the region
without resistance,path s1.So the overall circuit becomes like the original circuit above.The r at s2 have no effect onn the current reading

option b rite--i think u know why.Its exactly similar to above circuit.No current flow to the bottom R thus,same ammeter reading

option d rite-----no current flow as switch all open.No complete cicruit

Option c is WRONG.When s1 is open n S2 is closed,the current must now pass the extra resistor as it has no other chance.Thus overall resistance
is higher n current value is less than I.

 

[periyasamy]

Guys need help here.Please help.Thanks a lot.
Question 29--answer is c
Question 31--answer is c

 

[Jacob Park]

Could you guys help me plz?

 

[Abhi Mevawala]

 

[xyn1123]

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_s10_qp_12.pdf
Question 5

 

[x-gamer-x]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_12.pdf
Question 5

time for 8.5 cycles is 6 x time base setting i.e. 6x(0.01) = 0.06
time period = 0.06/8.5
frequency will be 1/Ans
its close to 140
so answer is B

 

[xyn1123]

time for 9.5 cycles is 6 x time base setting i.e. 6x(0.01) = 0.06
time period = 0.06/9.5
frequency will be 1/Ans
its close to 140
so answer is B

Is it 8.5 cycle?

 

[x-gamer-x]

Is it 8.5 cycle?

yup it is

i corrected

any ways my logic was correct

 

[xyn1123]

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_s08_qp_1.pdf
Q14, 18,24,37

 

[Jacob Park]

can I get some help again. thank you so much

 

[Jinosupreme]

Guys need help here.Please help.Thanks a lot.
Question 29--answer is c
Question 31--answer is c

29. As u put a screen to view ur interference pattern, u will definitely put at XY
31. U need to draw the positive and negative charge of the electric field. Which is positive on top, negative at bottom due to the direction of the electric field. Hence positive part of the Rod move to negative side. Negative part of rod move to positive side. The forces are in opposite direction, which causes 0 resultant force. But there is a torque, which will move in direction of anticlockwise of u imagine how the positive turns towards negative and the negative turns towards positive.

Hope this helps

 

[periyasamy]

29. As u put a screen to view ur interference pattern, u will definitely put at XY
31. U need to draw the positive and negative charge of the electric field. Which is positive on top, negative at bottom due to the direction of the electric field. Hence positive part of the Rod move to negative side. Negative part of rod move to positive side. The forces are in opposite direction, which causes 0 resultant force. But there is a torque, which will move in direction of anticlockwise of u imagine how the positive turns towards negative and the negative turns towards positive.

Hope this helps

Thank u.Have any question?