HSC Physics Predictions / Thoughts (6 Viewers)

NoUsername

Member
Joined
Oct 25, 2019
Messages
31
Gender
Male
HSC
2019
Also for question 17, what was the answer? I think I may have got this wrong, as I said D because the speed must be constant so it travels the same distance in the same time. I thought B and C were wrong because it should be the opposite, and A is obviously wrong.
 

Speed’o’sound Sonic

Well-Known Member
Joined
Nov 4, 2019
Messages
495
Gender
Male
HSC
2020
Wait... it was
Also for question 17, what was the answer? I think I may have got this wrong, as I said D because the speed must be constant so it travels the same distance in the same time. I thought B and C were wrong because it should be the opposite, and A is obviously wrong.
its C. Relativity of simultaneity, X sees the beam travel at c and Y at 1.95c that’s time dilation
 

henry_1234

New Member
Joined
Mar 5, 2019
Messages
3
Gender
Male
HSC
2020
Also for question 17, what was the answer? I think I may have got this wrong, as I said D because the speed must be constant so it travels the same distance in the same time. I thought B and C were wrong because it should be the opposite, and A is obviously wrong.
I thought C cause the back of the train moves towards the light but idk
 

NoUsername

Member
Joined
Oct 25, 2019
Messages
31
Gender
Male
HSC
2019
Wait... it was

its C. Relativity of simultaneity, X sees the beam travel at c and Y at 1.95c that’s time dilation
Isn't X within the inertial frame so that time is t0, while Y observes t, which is greater than t0, so it takes longer for Y? I just don't understand this question
 
Joined
Oct 31, 2020
Messages
74
Gender
Male
HSC
2020
Fingers crossed, if state rank cutoff falls below a 95 I reckon I could have a decent shot. Anyone have predictions for what mark they’re feeling before answers come out?
i feel good enough rn too
made quite a few mc silly mistakes (3-4 im guessing at least) but apart from that i may have lost 2-4 marks in the rest of the paper, it felt good and i had time to take a piss after too
 

Esdog07

New Member
Joined
Dec 2, 2019
Messages
9
Gender
Male
HSC
2020
I think I said withdraw the rods. The questions says the liquid slows down neutrons to increase the rate of fission (this part doesn't make sense to me, though) so if the liquid leaks, to compensate, you need to do something to increase the rate. As the rods absorb neutrons, they slow the rate, so I think it was A, at least that's what I said
I put A – withdraw the rods.

Its true that rods absorb the neutrons and the question states that the moderator increases the rate of fission. So putting the control the rods further into the reactor core would cause more neutrons to be absorbed while withdrawing them will cause fewer neutrons to be absorbed, thus increasing rate of fission
 

Speed’o’sound Sonic

Well-Known Member
Joined
Nov 4, 2019
Messages
495
Gender
Male
HSC
2020
i feel good enough rn too
made quite a few mc silly mistakes (3-4 im guessing at least) but apart from that i may have lost 2-4 marks in the rest of the paper, it felt good and i had time to take a piss after too
Yeah the multi’s threw me, I think I’m looking at a 17, cause I got the fission one, the Hertzprung one and the Io one all wrong :(
Rest of paper was heaps breezy though. Hopefully looking at a 95+ (Hopefully
 

NN03

New Member
Joined
Jan 14, 2020
Messages
19
Gender
Male
HSC
2020
I put A – withdraw the rods.

Its true that rods absorb the neutrons and the question states that the moderator increases the rate of fission. So putting the control the rods further into the reactor core would cause more neutrons to be absorbed while withdrawing them will cause fewer neutrons to be absorbed, thus increasing rate of fission
Could D (reduce the temp of coolant before pumping into core) be a viable option as lower temperatures lower the kinetic energy of the ejected neutrons, thus slowing them down indirectly?
 
Joined
Oct 31, 2020
Messages
74
Gender
Male
HSC
2020
A – you don't need brushes in ac induction motor.
Thats why it is a frictionless motor
yeah you dont need brushes for the rotor but you dont even need an electric current (*applied to the rotor*) so it could be d
 

ktbffh11

Member
Joined
Jan 8, 2018
Messages
47
Gender
Male
HSC
2018
A – you don't need brushes in ac induction motor.
Thats why it is a frictionless motor
nah not true - it's definitely D. the current in the rotor is induced - brushes are used to provide current to the stator that creates a rotating magnetic field
 

Xanthi

Active Member
Joined
Jul 4, 2020
Messages
208
Gender
Undisclosed
HSC
2020
nah not true - it's definitely D. the current in the rotor is induced - brushes are used to provide current to the stator that creates a rotating magnetic field
Yes!!!! I did D, was so scared
 

Speed’o’sound Sonic

Well-Known Member
Joined
Nov 4, 2019
Messages
495
Gender
Male
HSC
2020
You don’t need brushes in an AC motor if you’re talking about question 2. You do need a stator coil
 

Users Who Are Viewing This Thread (Users: 0, Guests: 6)

Top