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March 29, 2024, 10:46:30 pm

Author Topic: VCE Physics Question Thread!  (Read 603580 times)  Share 

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knightrider

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Re: VCE Physics Question Thread!
« Reply #420 on: April 27, 2014, 09:01:10 pm »
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how would you do these questions

Calculate the energy in electronvolts of
a)an alpha particle with 8.5*10^-12 J of energy
b)a beta particle with 6.4*10^-11 J of energy
c)a gamma ray with 4.7*10^-11 J of energy

Alwin

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Re: VCE Physics Question Thread!
« Reply #421 on: April 30, 2014, 02:26:04 pm »
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how would you do these questions

Calculate the energy in electronvolts of
a)an alpha particle with 8.5*10^-12 J of energy
b)a beta particle with 6.4*10^-11 J of energy
c)a gamma ray with 4.7*10^-11 J of energy

Hint: 1 eV = 1.6×10−19 J

Eg for (a) we have:  8.5*10^-12 / (1.6×10−19) = 53 052 829.4 eV (or equivalent scientific notation)

You can try the rest yourself :)
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Rishi97

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Re: VCE Physics Question Thread!
« Reply #422 on: April 30, 2014, 04:37:57 pm »
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ok so I got my physics EPI project info today and I found out that I have to design a circuit using either resistors, led or diodes. We had to buy this short circuit kit from jaycar and our EPI can only be made using the components which are spring connectors, battery holders, and all the basic electronic components.
I have no idea what to investigate. Any ideas would be greatly greatly appreciated :)
A massive thanks  :D Pls help me
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Stevensmay

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Re: VCE Physics Question Thread!
« Reply #423 on: April 30, 2014, 06:06:05 pm »
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ok so I got my physics EPI project info today and I found out that I have to design a circuit using either resistors, led or diodes. We had to buy this short circuit kit from jaycar and our EPI can only be made using the components which are spring connectors, battery holders, and all the basic electronic components.
I have no idea what to investigate. Any ideas would be greatly greatly appreciated :)
A massive thanks  :D Pls help me
What does 'all the basic electronic components' actually entail?

Rishi97

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Re: VCE Physics Question Thread!
« Reply #424 on: April 30, 2014, 06:11:05 pm »
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Diodes, resistors, LEDS, globes (it has more things but we are allowed to only use these)
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Stevensmay

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Re: VCE Physics Question Thread!
« Reply #425 on: April 30, 2014, 06:25:56 pm »
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Diodes, resistors, LEDS, globes (it has more things but we are allowed to only use these)

I asked for clarification just because it didn't seem like much sorry :).

Maybe a row of LED's with different brightness? Honestly I can't think of much you can do with that (at this level).

Rishi97

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Re: VCE Physics Question Thread!
« Reply #426 on: April 30, 2014, 06:51:39 pm »
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I asked for clarification just because it didn't seem like much sorry :).

Maybe a row of LED's with different brightness? Honestly I can't think of much you can do with that (at this level).

Yeah..,that's why it's so hard to choose an investigation. So when you said have a row of LED's, what exactly would I be measuring?
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Stevensmay

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Re: VCE Physics Question Thread!
« Reply #427 on: April 30, 2014, 07:11:51 pm »
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The effect of doubling resistance on brightness or something? Or different configurations of resistors eg series/parellel

Rishi97

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Re: VCE Physics Question Thread!
« Reply #428 on: April 30, 2014, 07:16:49 pm »
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The effect of doubling resistance on brightness or something? Or different configurations of resistors eg series/parellel

sounds great but how would I prove that the brightness has improved? Don't I need like some sort of measuring device?
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Orb

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Re: VCE Physics Question Thread!
« Reply #429 on: April 30, 2014, 08:08:38 pm »
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Hey guys,

bit stuck on this question:

In a laboratory class at school, Lee is given a spring with a stiffness of 15.4 N m–1 and unstretched length of 0.40 m. He hangs it vertically, and attaches a mass to it, so that the new length of the spring is 1.10 m when the mass is stationary. Assuming the spring has no mass, what was the value of the mass he attached?

Thanks!
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Rishi97

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Re: VCE Physics Question Thread!
« Reply #430 on: April 30, 2014, 08:22:26 pm »
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Hey guys,

bit stuck on this question:

In a laboratory class at school, Lee is given a spring with a stiffness of 15.4 N m–1 and unstretched length of 0.40 m. He hangs it vertically, and attaches a mass to it, so that the new length of the spring is 1.10 m when the mass is stationary. Assuming the spring has no mass, what was the value of the mass he attached?

Thanks!

I got 0.18kg. Do you have the answers?
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Orb

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Re: VCE Physics Question Thread!
« Reply #431 on: April 30, 2014, 08:25:18 pm »
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I got 0.18kg. Do you have the answers?

it's 1.08.. :/
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Rishi97

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Re: VCE Physics Question Thread!
« Reply #432 on: April 30, 2014, 08:40:15 pm »
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it's 1.08.. :/

ohhh. I'm waay off then. This is what I did....can someone please tell me where I'm going wrong
Us= 1/2kx2
    =1/2 x 15.4 x 0.72
    = 3.78 J
Since Us is 3.78 J, gpe must be 3.78
3.78 = mgh
And then I found mass by using the height as 1.1.
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Stevensmay

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Re: VCE Physics Question Thread!
« Reply #433 on: April 30, 2014, 08:58:51 pm »
+2

The mass will pull the spring down with a force equal to its mass * gravity.
Therefore the force exerted on the spring is

We also know that

Therefore

x will be equal to the change in the springs length, so 1.1-0.4 = 0.7
k = 15.4
Substituting in and rearranging gives 1.08.
(I've left out all the negative signs so this isn't strictly true.)
« Last Edit: April 30, 2014, 09:10:06 pm by Stevensmay »

Zealous

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Re: VCE Physics Question Thread!
« Reply #434 on: April 30, 2014, 09:03:25 pm »
+2
I'm getting a different answer of 1.72...

The mass will pull the spring down with a force equal to its mass * gravity.
Therefore the force exerted on the spring is

We also know that

Therefore

Substituting in and rearranging gives 1.72 which is wrong.
(I've left out all the negative signs so this isn't strictly true.)
Looks alright?





If we define downwards as being positive, our change in x (of the spring) will be a positive value as well as our acceleration of gravity so I don't think we'll encounter any negative answers.
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