Physics Paper 23

[alevelstudyhard]

How was the exam? What is the expected gt? Sorry wrong post just now.

 

[monkeys12]

was not expecting the electromagnetic spectrum!! how did you go?

 

[alevelstudyhard]

I think I did wrong for question 3. I used 600W instead of 576W for the last parts of the section, so have hard time proving the proportionality. But it was stated " Use the given information in (ii) and your answer in (iv)". I am assuming there is a difference between the 2 bolded sentence and that was why I used 600W. And for balancing nuclear equation, I wrote 4He2 and ended up puzzled since I can't balance it whatsoever. That was just a huge mistake.

Overall, quite a straight forward and short paper, so the gt may be higher somehow.

 

[Kandinsky]

The same, didn't expect spectrum... although I defined all the names, I hadn't recalled their wavelengths correctly. what about you, guys?
A little bit worried about the explanations and accuracy. Do you use 3 s.f. in answers?

 

[DominicD]

What did you all get for the Resistive force?

 

[roneyms]

I think the resistive force was 42N. It turns out to be proportional with k=3.

 

[roneyms]

As for S.F, we're supposed to use the same SF as given in the question.

 

[DominicD]

I'm pretty sure from the first part, the R is 48N, and v=12ms-1. So the k must be 4 for part i.

 

[Rickster]

For resistive force, don't you also have to take into account the accelerating force to accelerate it around 0.5
Also, what did you guys get for the names of the waves and the resultant velocity of the plane?

 

[roneyms]

Resultant is 32N(someone said 35N, so yeah) for v=8.0 ms-1 (acc. 0.5 ms-2)

I wrote colours of the waves since they said NEAR 500nm. I may be wrong. Velocity of the plane is....225 or something.

 

[roneyms]

Since Power is constant
576/8=R
Resultant Force=72N
Subst. it below


72N-R=80X0.5
R=32N
Well was the combined mass 80kgs? Than this should be the answer for the next part of finding the R

Thanks

 

[roneyms]

and I think....I got k=4...It has been some days so I got a bit, you know.

 

[DominicD]

Thanks. I got 32N for R too.

As for the resultant velocity, I used the scale and I got 11.3cm, equivalent to 226ms-1.

 

[roneyms]

Welcome. Which chool are you from?

I used the calculations method xD

 

[Rickster]

Thanks for that
How did you get the resultant velocity by using the scale. Did you move the vector downwards, along the plane vector, and then joined up the triangle???

 

[Rickster]

Downwards to the end, keeping the same angle. That's what i did and I got 230

 

[DominicD]

When it comes to scale drawing, Cambridge are usually very strict about it. Just use the usual vector addition method. Btw I'm from Malaysia.

 

[Patterson]

Hey guys, I've got some questions about that paper.

1. Where exactly did you guys draw the resultant velocity vector?
2. What did you guys get for the new height of BC when the angle becomes 30 degree (and it told you to use the law of energy conservation)?
3. What did you get for/how did you answer the question about internal resistance using that graph?
4. What did you write for the explanation about the acceleration as the mass travels from A to B then to C on the slope

Thanks

 

[DominicD]

For the resultant velocity, just connect the tail of the wind velocity to the head of the plane velocity, then connect them both with a resultant velocity. You'll get some sort of triangle shape. It's hard to put it in words.

The new height of BC is still the same as AB, I think it's around 0.28m. What they asked for is the new distance. The new distance is 0.28/sin30 = 0.56m

E = V + Ir, --> V= -Ir + E, so -(gradient)=internal resistance, it should be around 1.81ohm.

For the acceleration, I wrote constant acceleration of gsin15 from A to B (or B to C, I'm not exactly sure) then constant deceleration of -gsin30 from B to C. I'm not exactly sure how to score all 3 marks, so well.

 

[roneyms]

Oh I am from Brunei.

Only Brunei and Malaysia are sitting for P23. Any paper ending with 3 practically.

All the best!