# General Thoughts: Physics (1 Viewer)

#### Sarthakgarg

##### New Member
why is it a parabolic path rather than a linear?
I related it to Thompson's charge to mass ratio and said that the force due to electric field equals centripetal force on the electrons....

#### Sarthakgarg

##### New Member
Someone post the MCQ's pls....

#### malcolm21

##### Active Member
it was like a table and it said choose the correct contribution of einsten and planck to quantum theory or something
a

btw, did anyone talk about the circuit not being closed in the electron deflection one? I dont know if thats right

I agree

#### knightus10

##### Member
I hated that last space question. Screwed me over so much. Probably got 2/6 for that. And Probs lost 3 marks on the super conductor. Gahhh how does one get the velocity of the electron?!?!? Idk. It was ok, but on the harder part of 'ok'. I guess I should be relieved that HSC is over for me

##### Member
I hated that last space question. Screwed me over so much. Probably got 2/6 for that. And Probs lost 3 marks on the super conductor. Gahhh how does one get the velocity of the electron?!?!? Idk. It was ok, but on the harder part of 'ok'. I guess I should be relieved that HSC is over for me
use the force from part a to find the acceleration, then plug acceleration into v^2=u^2+2as

#### knightus10

##### Member
use the force from part a to find the acceleration, then plug acceleration into v^2=u^2+2as
But doesn't that only apply for projectile motion. Wasn't the electron going straight to the right?

#### apurba

##### Member
use the force from part a to find the acceleration, then plug acceleration into v^2=u^2+2as
i used the force to find WORK

W=Fs

then equated this value to kinetic energy: E=1/2mv^2

to find velocity

#### karan96

##### New Member
use the force from part a to find the acceleration, then plug acceleration into v^2=u^2+2as
yep did that too, is it right tho? do you remember your answer

##### Member
But doesn't that only apply for projectile motion. Wasn't the electron going straight to the right?
projectile motion uses horizontal and vertical components anyway so its the same thing

##### Member
yep did that too, is it right tho? do you remember your answer
it had 5 digits, thats all i remember lmao, possibly starting with a 2

#### p0llex

##### Member
But doesn't that only apply for projectile motion. Wasn't the electron going straight to the right?
It still applies for things which aren't projectiles, but in this case the electrons have some initial velocity which we don't know.

Best way of doing it I think was using qV=1/2mv^2, answer turned out to be somewhere between 7000 and 8000

#### apurba

##### Member
it had 5 digits, thats all i remember lmao, possibly starting with a 2
i got like 4.7x10^7 m/s

#### astroman

##### Well-Known Member
That was pretty tough, and wtf there was only like 10/55 marks worth of space related questions.

#### InteGrand

##### Well-Known Member
$\bg_white The formula v^2 = u^2 + 2a\Delta s, where \Delta s is the change in position from the initial position at time t, applies for any 1-D motion with \emph{constant} acceleration a, where the initial velocity is u and the velocity at time t\geq 0 is v.$

#### malcolm21

##### Active Member
does anybody know if my reasoning that the electric circuit wasn't closed (that 2 cm gap) means electrons cant be liberated from cathode and accel towards anode? i wrote that + electrons are - charge so its deflecting wrong way

##### Member
That was pretty tough, and wtf there was only like 10/55 marks worth of space related questions.
There was heaps of space stuff, what you talking about

#### sy37

##### Active Member
For the one where you had to sketch a graph of the copper going under the magnet, am I the only one who let the decrease in velocity curve go well throgugh C and back up just before D? Because the end of the copper still touches. I think that might have tricked some people

pretty fucking hard exam imo..averaged 80% in MC for past papers, expecting like 60% here because I was barely sure.....am I the only one who got BARELY like 1-2 D's only?

Some questions were nice, others worded poorly..gg tough exam fuck

#### astroman

##### Well-Known Member
There was heaps of space stuff, what you talking about
there was too much of the other topics.

#### snail489

##### Member
I used integration for more than one question LOL i got the answer but do i get marks
heh I did this too to get the velocity of the electron as it reaches anode... pretty sure I got the correct answer but just praying that they don't deduct marks since i literally forgot about using projectile motion formulas