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March 29, 2024, 06:41:55 am

Author Topic: VCE Physics Question Thread!  (Read 603344 times)  Share 

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Gogo14

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Re: VCE Physics Question Thread!
« Reply #1830 on: August 15, 2017, 05:05:32 pm »
0
Hey guys can you guys help me with q8-10
http://imgur.com/a/PFS6W
Dont really understand the answers thanks
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Re: VCE Physics Question Thread!
« Reply #1831 on: August 15, 2017, 07:42:14 pm »
+3
Hey guys can you guys help me with q8-10
http://imgur.com/a/PFS6W
Dont really understand the answers thanks

You need to look at the graph and identify which letter on it best reflects the question. For example, in a compression the particles are close together, and in the graph the position where they are close together is at "c".

Shadowxo

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Re: VCE Physics Question Thread!
« Reply #1832 on: August 15, 2017, 08:18:40 pm »
+2
I'd also recommend looking at an animation of a longitudinal wave and looking back over your notes :)
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chantelle.salisbury

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Re: VCE Physics Question Thread!
« Reply #1833 on: August 17, 2017, 10:02:32 am »
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hi
the time has come to do the extended investigation. i was wanting to do something regarding the young's experiment. however, i didnt know what or how to turn this into a good question. are there any suggestions?
i have thought about investigating the width of the bands produced and then having 2 independent variables to investigate. would this be sufficient for the entire prac considered it is constructed and investigated well?

thankyou :)

Syndicate

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Re: VCE Physics Question Thread!
« Reply #1834 on: August 19, 2017, 02:26:57 pm »
+3
hi
the time has come to do the extended investigation. i was wanting to do something regarding the young's experiment. however, i didnt know what or how to turn this into a good question. are there any suggestions?
i have thought about investigating the width of the bands produced and then having 2 independent variables to investigate. would this be sufficient for the entire prac considered it is constructed and investigated well?

thankyou :)
That should be fine. I think a good question can be (I am not sure what your independent variables are): How does visible light of different wavelengths affects the width of the bands produced on the screen?

So you can investigate the affects of red and blue light for instance.
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BlinkieBill

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Re: VCE Physics Question Thread!
« Reply #1835 on: August 26, 2017, 03:56:16 pm »
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Hey,
Why is the single slit (in the double slit experiment) required to make the light sources coherent?
Thanks
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Syndicate

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Re: VCE Physics Question Thread!
« Reply #1836 on: August 26, 2017, 04:39:12 pm »
+4
Hey,
Why is the single slit (in the double slit experiment) required to make the light sources coherent?
Thanks

Incoherent light waves will not have the same frequency (as basically the troughs and crests will be randomly distributed). When the incoherent light wave passes through a single slit, the majority of the wave focuses at the centre, hence making it coherent. How? Lets think about a bunch of marbles and a small opening. If you try to push all the marble through the opening at the same time, will they get through? Offcourse not. Whereas, if you put them in one by one, you will see that all the marbles get through (mainly aiming the centre) are the same distance apart (assuming you are releasing them at the same time). This is basically how a coherent light wave forms. A requirement to produce an interference pattern is for a wave to have the same frequency (and amplitude) when passing double slits in order to produce nodal and anti-nodal regions.
« Last Edit: August 26, 2017, 04:49:50 pm by Syndicate »
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Re: VCE Physics Question Thread!
« Reply #1837 on: September 13, 2017, 08:44:15 pm »
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Hey everyone, I need help with my physics epi.

So in my experiment I dropped a car down a inclined plane from 30°, 35° and 40° (Twice).The car was 800grams.  I dropped the car with no weight so 800grams then I added a 1kg weight towards the middle of the car and dropped it from same angle. (Recorded the time it went down) 

So my question is I want to calculate the acceleration right. I was going to use a=gsin(θ) but then I realised I need to use this formula 6 times. The problem was that for 30° for example I was going to use a=9.8sin(30) but then I looked back at my results and I saw the problem. What was I going to do with the 30° angle with 1kg extra weight on the car.? According to that calculation^ the acceleration would be the same as the car with weight but it's supposed to be different.

My partner suggested that we should use
v=u+at^2 then transpose to a=v/t^2. Then use a=f/m.

I feel like this is wrong. Can someone please help me out.

If you didn't understand my experiment I can explain again in further detail.
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Shadowxo

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Re: VCE Physics Question Thread!
« Reply #1838 on: September 13, 2017, 09:13:54 pm »
+3
Hey everyone, I need help with my physics epi.

So in my experiment I dropped a car down a inclined plane from 30°, 35° and 40° (Twice).The car was 800grams.  I dropped the car with no weight so 800grams then I added a 1kg weight towards the middle of the car and dropped it from same angle. (Recorded the time it went down) 

So my question is I want to calculate the acceleration right. I was going to use a=gsin(θ) but then I realised I need to use this formula 6 times. The problem was that for 30° for example I was going to use a=9.8sin(30) but then I looked back at my results and I saw the problem. What was I going to do with the 30° angle with 1kg extra weight on the car.? According to that calculation^ the acceleration would be the same as the car with weight but it's supposed to be different.

My partner suggested that we should use
v=u+at^2 then transpose to a=v/t^2. Then use a=f/m.

I feel like this is wrong. Can someone please help me out.

If you didn't understand my experiment I can explain again in further detail.
For a larger mass, the force is greater. So F/m is constant (on the same incline). It's like that experiment with the feather and the heavy ball, they both fall at 9.8 m/s2 (neglecting air resistance). So, you're right in that the acceleration just depends on the angle :) You could take into account friction but again that wouldn't be different for different weights (N=mgcos(theta) on an incline so F/m = gcos(theta)).

Also, for your experiment you should compare your experimental values (using the data from the experiment) to theoretical (a=g sin(theta)). You could find reasons for why your experimental values different from theoretical - eg friction as mentioned above, or air resistance etc

Hope this helps :)
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Willba99

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Re: VCE Physics Question Thread!
« Reply #1839 on: September 13, 2017, 09:14:39 pm »
+1
Hey everyone, I need help with my physics epi.

So in my experiment I dropped a car down a inclined plane from 30°, 35° and 40° (Twice).The car was 800grams.  I dropped the car with no weight so 800grams then I added a 1kg weight towards the middle of the car and dropped it from same angle. (Recorded the time it went down) 

So my question is I want to calculate the acceleration right. I was going to use a=gsin(θ) but then I realised I need to use this formula 6 times. The problem was that for 30° for example I was going to use a=9.8sin(30) but then I looked back at my results and I saw the problem. What was I going to do with the 30° angle with 1kg extra weight on the car.? According to that calculation^ the acceleration would be the same as the car with weight but it's supposed to be different.

My partner suggested that we should use
v=u+at^2 then transpose to a=v/t^2. Then use a=f/m.

I feel like this is wrong. Can someone please help me out.

If you didn't understand my experiment I can explain again in further detail.

I believe that the integral idea from your experiment should be that weight has no effect on acceleration. Have you ever seen the video where they drop a feather a bowling bowl in a vacuum, and they fall at the same rate? i would suggest that if your experiment gives you drastically different values when you add the weight then you're doing something wrong
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Willba99

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Re: VCE Physics Question Thread!
« Reply #1840 on: September 13, 2017, 09:15:47 pm »
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For a larger mass, the force is greater. So F/m is constant (on the same incline). It's like that experiment with the feather and the heavy ball, they both fall at 9.8 m/s2 (neglecting air resistance). So, you're right in that the acceleration just depends on the angle :) You could take into account friction but again that wouldn't be different for different weights (N=mgcos(theta) on an incline so F/m = gcos(theta)).

Also, for your experiment you should compare your experimental values (using the data from the experiment) to theoretical (a=g sin(theta)). You could find reasons for why your experimental values different from theoretical - eg friction as mentioned above, or air resistance etc

Hope this helps :)

lol beat me to it
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Re: VCE Physics Question Thread!
« Reply #1841 on: September 13, 2017, 10:38:10 pm »
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Thanks for the reply's.

I believe that the integral idea from your experiment should be that weight has no effect on acceleration.
My research question is measuring energy released. So going to calculate the potential energy and kinetic energy on the incline.

Also my values are similar with the weight ontop of car. So I don't think I'm doing anything wrong just yet lol.
On a side note I'm going to calculate the components (perpendicular and parallel) acceleration (as said before) and the energys. Should be enough I think.

For a larger mass, the force is greater. So F/m is constant (on the same incline). It's like that experiment with the feather and the heavy ball, they both fall at 9.8 m/s2 (neglecting air resistance). So, you're right in that the acceleration just depends on the angle :) You could take into account friction but again that wouldn't be different for different weights (N=mgcos(theta) on an incline so F/m = gcos(theta)).

Also, for your experiment you should compare your experimental values (using the data from the experiment) to theoretical (a=g sin(theta)). You could find reasons for why your experimental values different from theoretical - eg friction as mentioned above, or air resistance etc

Hope this helps :)

Thanks for the detailed answer but I just got completely confused. So do I go and use a=gsin(theta) or my partners method (a=v/t^2)


So which method is correct for 30°
Method 1) a=gsin(theta) therefore a=9.8sin(30)=4.9
Therefore acceleration= 4.9ms^-2

Or
Method 2)v=s/t therefore 1.5/0.86=1.74 therefore  a=v/t^2 therefore 1.74/0.86^2=2.35
Therefore acceleration= 2.35ms^-2

Which method is correct 1 or 2?

Edit those were some of my results so don't get confused by numbers. ;D
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Shadowxo

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Re: VCE Physics Question Thread!
« Reply #1842 on: September 13, 2017, 11:04:46 pm »
+3
Thanks for the reply's.
My research question is measuring energy released. So going to calculate the potential energy and kinetic energy on the incline.

Also my values are similar with the weight ontop of car. So I don't think I'm doing anything wrong just yet lol.
On a side note I'm going to calculate the components (perpendicular and parallel) acceleration (as said before) and the energys. Should be enough I think.

Thanks for the detailed answer but I just got completely confused. So do I go and use a=gsin(theta) or my partners method (a=v/t^2)


So which method is correct for 30°
Method 1) a=gsin(theta) therefore a=9.8sin(30)=4.9
Therefore acceleration= 4.9ms^-2

Or
Method 2)v=s/t therefore 1.5/0.86=1.74 therefore  a=v/t^2 therefore 1.74/0.86^2=2.35
Therefore acceleration= 2.35ms^-2

Which method is correct 1 or 2?

Edit those were some of my results so don't get confused by numbers. ;D
You may need to look over / revisit some equations.
v = u + at   (not at2)
s=vt only works for a constant or average velocity,  not when you want to calculate the final velocity

a=9.8sin(30) is the acceleration you expect - the theoretical value. It doesn't use your data, just is an expectation.

To find your experimental acceleration, think of the different physics formulas - which has all the variables you want? You know the distance travelled, initial speed, time taken and want to find acceleration. You'd use this formula for your results :)
If you want to find v instead for energy, you'd either use the acceleration from before or another physics formula
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Re: VCE Physics Question Thread!
« Reply #1843 on: September 13, 2017, 11:29:32 pm »
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You may need to look over / revisit some equations.
v = u + at   (not at2)
s=vt only works for a constant or average velocity,  not when you want to calculate the final velocity

a=9.8sin(30) is the acceleration you expect - the theoretical value. It doesn't use your data, just is an expectation.

To find your experimental acceleration, think of the different physics formulas - which has all the variables you want? You know the distance travelled, initial speed, time taken and want to find acceleration. You'd use this formula for your results :)
If you want to find v instead for energy, you'd either use the acceleration from before or another physics formula

Oops I just realised lol sorry I meant v=u+at.

Ok so I'm going to use one of the 5 formulas. Thanks!
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Re: VCE Physics Question Thread!
« Reply #1844 on: September 19, 2017, 12:30:22 pm »
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so we did a prac where we dropped magnets through solenoids the other day,
and we got the graphs that look like one period of a positive sine graph.

What can we do with this graph? use emf = -N d(flux)/dt  to calculate what the change in flux was? is this the equation for average emf? and do we use the peak values for this?

is finding the area under the graph to calculate the strength of the magnets possible???