VCE Physics Question Thread!

[LE-0130]

Hi!
I was just hoping to get help for this physics question. I'm sort of new to mechanical waves and I don't quite understand the answer for this question. Any help would be appreciated! Thanks 

[Bri MT]

Hi!

Welcome to the forums

This question is testing your understanding of how transverse waves work. Imagine that the graph is showing an ocean wave,  you if you picked one location in the ocean, the water level would go up and down and up and down as the wave moves along. For this question, the locations you are interesting in are u and v - where are those particles going?

It might help you to watch a video or look at a gif explaining the basics of transverse waves if you're finding this very confusing.

[Cupcake2423]

hey!!

i know for the end of year exam i'm allowed to type up my notes (and its 2 double-sided A4 paper right??)

But for my SACs can i also type up my notes (like the summary sheet)??

[Owlbird83]

hey!!

i know for the end of year exam i'm allowed to type up my notes (and its 2 double-sided A4 paper right??)

But for my SACs can i also type up my notes (like the summary sheet)??

Hey!
yep for size of exam notes

I'm sure you would be able to type and print out sac cheat sheets, I don't see why teachers wouldn't accept that unless they've told people it must be handwritten. I guess it depends on your school/teacher, but my school was fine with whatever for sacs so long as it was the size they told us 

[Roger Luo]

I am quite ahead for physics, and don't know what to do, right now I am done in Unit 3 for physics, but our school is only halfway through it, should I start revising practice exams for unit 3, or get the other jacaranda book and do the questions of that. tbh, I don't know how to juggle Unit 3 review with stronger SAC prep.

[Coolmate]

I am quite ahead for physics, and don't know what to do, right now I am done in Unit 3 for physics, but our school is only halfway through it, should I start revising practice exams for unit 3, or get the other jacaranda book and do the questions of that. tbh, I don't know how to juggle Unit 3 review with stronger SAC prep.

Hey Roger Luo!
Welcome to the forums

It is great that you are ahead for VCE Physics, I didn't do VCE Physics, but I do strongly suggest starting practice questions early. The thing that really helped me during my HSC was applying the content to questions, rather than straight memorisation as you can get any question on the day.

If you run out of questions from past VCE papers, you could go through past HSC papers here and here and sort out any relevant questions to the VCE syllabus.

Good luck with everything
Coolmate

[ErnieTheBirdi]

I need help... I've been hitting the fan with physics recently. Getting 49% ( still pass) and a 50% on the first two AOS so far for U3... Am I screwed if I want a good study score? like Raw 35+? HELP ME

[Samueliscool223]

Why is answer A here wrong (q. 12)? isnt the velocity function a linear equation for objects falling under the influence of gravity, and hence isnt the speed of da object increasing at a constant rate? i wouldve thought both A and C are correct but apparently its just C

[Rachelrachel]

Hey guys, I'm completing some Unit 1&2 conservation of momentum questions and am really confused by this one.

"a railway wagon of mass 2.5 tonnes moving along a horizontal track at 2 m/s runs into a stationary engine and is coupled to it. After the collision, the engine and the wagon move off at 0.3 m/s. What is the mass of the engine alone?"

I used this formula:

m₁u₁ + m₂u₂ = m₃v₃

to obtain:

2.5*2+0 = (2.5+m)*0.3

This resulted in m=14.17 tonnes. However, my textbook says that 4.2 tonnes is correct. I have no idea how to obtain this answer.

Can anyone offer any insight?

[ArtyDreams]

Hey guys, I'm completing some Unit 1&2 conservation of momentum questions and am really confused by this one.

"a railway wagon of mass 2.5 tonnes moving along a horizontal track at 2 m/s runs into a stationary engine and is coupled to it. After the collision, the engine and the wagon move off at 0.3 m/s. What is the mass of the engine alone?"

I used this formula:

m₁u₁ + m₂u₂ = m₃v₃

to obtain:

2.5*2+0 = (2.5+m)*0.3

This resulted in m=14.17 tonnes. However, my textbook says that 4.2 tonnes is correct. I have no idea how to obtain this answer.

Can anyone offer any insight?

Hi! Your working out is correct but you have to make sure that you convert the tonnes to kilograms. In the formula p=mv, mass is in kilograms and v is in m/s, to get your momentum being kg/m/s. Hope this helps!

[Rachelrachel]

you have to make sure that you convert the tonnes to kilograms.

1 tonne = 1000 kg. Therefore converting to kg doesn't change the actual digits of the answer, only its magnitude (the mass works out to be 14167 kg instead of 14.17 tonnes). I'm still stuck on how the textbook gets an answer of 4200 kg.

[ashmi]

Hey guys, I'm completing some Unit 1&2 conservation of momentum questions and am really confused by this one.

"a railway wagon of mass 2.5 tonnes moving along a horizontal track at 2 m/s runs into a stationary engine and is coupled to it. After the collision, the engine and the wagon move off at 0.3 m/s. What is the mass of the engine alone?"

I used this formula:

m₁u₁ + m₂u₂ = m₃v₃

to obtain:

2.5*2+0 = (2.5+m)*0.3

This resulted in m=14.17 tonnes. However, my textbook says that 4.2 tonnes is correct. I have no idea how to obtain this answer.

Can anyone offer any insight?

First things first, I don't see anything wrong with your working out here. Just as Arty has mentioned above, it would be preferable if you kept the momentum to kg/m/s (just in case you lose track of units). I believe your answer (14.17 tonnes) is correct.

[parieeelol]

Hey guys - I've been stuck on this question for a while now, and I believe it's asking for the angle of emergence, but I have no idea how to calculate it and the solutions aren't making sense. (Unit 4 Physics, AOS1)

The angle of incidence was calculated to be 48 degrees, and angle of refraction as it enters the prism was 28.6 degrees. I used Snell's Law for both. But other than that, I have no idea how to tackle this question and would appreciate any help.

[SmartWorker]

Hey guys - I've been stuck on this question for a while now, and I believe it's asking for the angle of emergence, but I have no idea how to calculate it and the solutions aren't making sense. (Unit 4 Physics, AOS1)

The angle of incidence was calculated to be 48 degrees, and angle of refraction as it enters the prism was 28.6 degrees. I used Snell's Law for both. But other than that, I have no idea how to tackle this question and would appreciate any help.

Hi, i tried the question, i don't know if my solution is correct but i hope this at least helps a bit.

So yep the angle of refraction = 28.6 degrees.

Then notice: the triangle is equilateral. Make a right angled triangle (should be able to do this as the dotted line is the normal line) and then you can solve from there.

[miyukiaura]

Hey guys, I just had a question about refraction: why is it that when light refracts into a different medium, its velocity and wavelength change but frequency remains constant? I would have thought that frequency is inversely proportional to wavelength so as e.g. wavelength increases, frequency decreases?
Thanks!