Some Tips (1 Viewer)

[helper]

hey helper,
can u post up some applying questions similar to the ones in last years hsc.

Like the Back EMF one or like the Michael Jordan one?

PS. For the Back emf q, how many ppl would have answered that correctly, i suppose not many would have

Don't know anymore than what is in the markers report, which sounds like it caused trouble.

 

[Haku]

the questions in the 2003 paper was really challenging. i did them today and they were really bad. though for chem the paper is still good.

can u post of questions testing on application of what we learnt in around 4-6 mark questions not just regurgitation.

 

[richz]

Like the Back EMF one or like the Michael Jordan one?

Don't know anymore than what is in the markers report, which sounds like it caused trouble.

both

thnx

PS: if u put the answers to them put them in spoilers, or a msg to anyone else whoever answers the questions can u put them in spoilers. thnx

 

[sikeveo]

they're in the success one book. Or on the bos website......

 

[Captain Gh3y]

Wait, what's this Back EMF question? (What year HSC?)

 

[richz]

Captain: 2004

sikeveo: i know, i want other questions.........

 

[richz]

Helper

did u see todays senior science test, were there qs where the cadidates had to answer in boxes

thnx

 

[helper]

I'll see what I can do for tomorrow Xtrc.
Captain, he is talking about Q 21. B.

A similar question to the Jordan question.

11. (4 marks)

1968 Mexico Olympics
The high altitude of Mexico City made life uncomfortable for the distance runners, but elsewhere Olympic and World records crashed.
A total of 34 World and 38 Olympic records were set, with the most outstanding being the new mark set by American Bob Beamon in the long jump. He beat the previous record by a massive 55cm as he leapt 8.90 m. A record that would stand for 20 years
American high jumper Dick Fosbury won gold with his 'flop' style that was to revolutionise the event and replace the conventional straddle technique.
The triple jump saw the previous Olympic record beaten by seven competitors and the world mark improved upon on five occasions.

Assess why the altitude of the Mexico Olympics resulted in so many world records in jumping.
Use mathematical formulas to support your answer.

 

[helper]

At my school, no-one does senior science so I haven't seen the paper.

 

[richz]

o ok thnx , do it when ever ur free, i dont mind

 

[sikeveo]

the jordan question wasn't that abstract. That mexico one is not as hard though.

 

[Jago]

I'll see what I can do for tomorrow Xtrc.
Captain, he is talking about Q 21. B.

A similar question to the Jordan question.

11. (4 marks)

Assess why the altitude of the Mexico Olympics resulted in so many world records in jumping.
Use mathematical formulas to support your answer.

Why did Q21 b cause so much trouble? personally i think a) was more difficult

 

[helper]

Most people just didn't recognize the idea of back emf. A lot of people learn the theory but not how it applies in the real world.

It is how they are trying to catch rote learners.

 

[Jago]

ah excellent. btw, what were teh 3 errors in a)? apart from the magnets being north?

would the brushes being copper be another one?


and finally, with the jordan question, did you need to show that change in y = 7.7m?

 

[richz]

there is nothing rong with the magnets.

3 mistakes:
1. no electrical connection
2. The commutator is not in the correct position, coz if the coils are in that position the commutator should be rotated 90 degrees
3. the coils on each side are wounded in different directions

EDIT: answer to ur jordan q, yes, and say that it is physically impossible for a person to jump that high

 

[helper]

What do you mean by the magnets being North?

Look at the wires for two of the errors.
The third is to do with the orientation of the coils and the torque that each side won't produce.

 

[helper]

would the brushes being copper be another one?

That is an improvement you could make but bot an error.

and finally, with the jordan question, did you need to show that change in y = 7.7m?

You had to do one calculation to show it was impossible not both.
The marking scheme is on the board's site.

 

[Jago]

ah i see, 0/3 for that bit then.

but at least i would've grabbed a bunch of marks for jordan

 

[Haku]

what yr is that jordan question?

y is it so famous?

and helper that olympics question what yr is it from? and whats the answer?
i thought that being in high altitudes the air is thinner so their lungs and red blood cells are more and bigger. So that on normal grounds they obtain more oxygen, which is the main component of energy source for the body so they perform better. whats the mathematical reason?

 

[Jago]

they're further away from the centre of the earth:

g (acceleration) = Gm/r²

so g is reduced, and thus the athlete's weight is reduced, allowing them to jump further/higher.