Physics Predictions/Thoughts (1 Viewer)

[Faye19]

Hey guys, one more request, please. Does anyone have a proper sample answer for this:

 

[Arrowshaft]

how do do this?

For this , you’d do your normal calculation of energy released and divide by 2 since there are 2 alpha particles which share the energy released.

 

[Faye19]

For this , you’d do your normal calculation of energy released and divide by 2 since there are 2 alpha particles which share the energy released.

can you please solve it?

 

[Drdusk]

I just want to say good luck for Physics tomorrow all of you!

Go and smash the exam! All of you on here are really capable students of Physics and I'm sure you'll ace it!

Just some final tips!

Remember do NOT rush through the paper, think DEEPLY about each question especially the mathematical ones. Think of any laws you can apply, any formulas you can equate because 90% of the time it comes down to equating formulas. For graph questions remember if you need to use the graph it's most likely your going to need to use the gradient of the graph which means the graph should be linear!

If you have no idea how to do a mathematical type question think of any two formulas you know are applicable to it and just equate them as a last resort(as long as you know it will help you find the variable your looking for).

Remember to FOLLOW the guidelines for long responses, for e.g. an explain question is relate cause and effect.

Remember you have a formula and data sheet. If you can't remember a formula or some data, don't panic! It's most likely on the formula or data sheet.

Do NOT round your answers or use any sig figs UNTIL the final answer. You may LOSE a decimal point or something if you do it early. Until you get to an expression for the final answer do NOT plug in any values.

Oh and you can do sig figs on your calculator.

You can also do trig ratios on your calculator. For example to find sin(45). Type it in just like that into your calculator, then straight away square the answer. Then convert it to a fraction on your calculator using the S<->D button your used to. This will give you an exact value for which you just need to write done the square root of.

Other than that, BEST OF LUCK from me and everyone else on BOS! =))


EDIT: Also it's very important to CHECK if your answer makes SENSE. For example in last years paper, some people came up with a velocity for a ball that had been thrown directly upwards as being greater than the velocity that it began with. This makes no sense! as gravity is constantly slowing the ball down! Always think "does this answer makes sense!?"
If you end up with a value for time in the thousands you might need to reconsider for eg

 

[dcosmo]

can you please solve it?

Calculate mass units for beryllium and subtract 2 x the mass units for 4 He.

Be: 8.005305
He: 4.002603 x 2 = 8.005206

Subtract them: 8.005305 - 8.005206 = 0.000099

Multiply this value by 931.5 MeV/c^2 = 0.0922 MeV

Divide by 2 for each alpha particle = 0.0461 MeV = 46.1 KeV = D

 

[Arrowshaft]

Hey guys, one more request, please. Does anyone have a proper sample answer for this:
View attachment 27551

Technology plays a crucial rule in developing new models and ideas of matter, especially in the frontier of particle physics - the Standard Model.

Particle accelerators such as the one at SLAC (Stanford linear accelerator centre) use linear accelerators to accelerate protons through a series of drift tubes 3 km long in total, where the gaps between each electrode serve to provide a 'kick' by exposing them to electric fields and accelerating them. The accelerating potential, which is alternating has to be kept in step with the particles, hence the tubes are lengthened.

Cyclotron (which have now been phased out), accelerate particles as they pass through the gaps between the two 'dees' giving them a kick and increasing their radii, speed and energy. A high frequency AC voltage is used to change the polarity of the dees every half rotation as the particles re-enter the gap to provide a uni-directional acceleration. When the particle reaches the limit of the magnetic field, deflector plates are used to fire them. There are many disadvantages to using cyclotrons however, as very high energy particles cannot be produced from it due to the limitations in size and energy requirements due to mass dilation results in the alternating potential to become out of step with the accelerating charges.

Synchrotrons keep particles in a constant radius, and as the particles get more energetic, a stronger magnetic field is used to maintain the same radius. Synchrotrons, such as the LHC use large superconducting magnets which cover 85% of the circumference and are 15 metres long, cooled by liquid helium to provide the magnetic field; as they do not heat up and can be used for long periods of time. The particles pass through a large diameter ring (as large as 6.28 km in FermiLab) where regions are exposed with radio frequencies to provide an electric field to accelerate the particles, these frequencies increase as particle energy increase. Colliders in FermiLab can acceleratre protons up to 200 GeV. Synchrotrons are the most favoured particle accelerators due to their few limitations, with the main one being the inability to fire more than one batch of particles at a time, however, this is just a minor issue in comparison to the capabilities it offers.

Particle accelerators, such as the state-of-the-art LHC, can accelerate protons to up to 7 TeV, these allow new discoveries to be made, as by colliding these particles at extremely high speeds we can observe their fragmentation and decomposition into newer fundamental particles, as such with the discovery of the Higgs Boson in 2012, which validated the Standard Model of matter by confirming Peter Higgs's hypothesis in the 1960's about the existence of a fundamental field that provides mass to particles. These discoveries have also been facilitated by the use of state-of-the-art detectors such as multicomponent detectors and calorimeters in the LHC at CERN, FermiLab and Brookhaven to record the trajectory, energy and momentum of particles formed, allowing further analysis of intrinsic details on new subatomic particles. These tracking chambers are contained within cylindrical shells as these collisions result in the distribution of the fragmentation in all directions radially, hence a wide surface area is required for accurate and precise detection.

Thus, the development of technology has vastly escalated our understanding of the standard model of matter, leading to revolutionary discoveries such as the Higgs Boson.

 

[Arrowshaft]

Sorry, kinda forgot what the question was asking half way haha, didn't double check so please be wary. Also, do not write this much by the way, I just wanted to give you some extra info @Faye19.

 

[Faye19]

@Arrowshaft , haha no worries, thank you so much. I really appreciate the help tonight.
All the best for the exam tomorrow.

 

[Arrowshaft]

Haha, I totally forgot it asked to include ONE other area in physics . Sorry about that! But that’s just basic description of technology anyway; you can talk about the Hafele Keating atomic clock experiment, Fizeau and Foucault in determining the speed of light, etc.

 

[TheOnePheeph]

Haha, I totally forgot it asked to include ONE other area in physics . Sorry about that! But that’s just basic description of technology anyway; you can talk about the Hafele Keating atomic clock experiment, Fizeau and Foucault in determining the speed of light, etc.

For the response on the standard model of matter, is the amount of stuff on particle accelerators really essential? As we really quickly went over that in class lol. Would you say its ok to instead talk about the technology in cathode rays to find the electron initially, as well as the development of x ray technology and microscopes for milikan to perform his oil drop experiment to show charge was quantised, then maybe talk about how nowadays early cyclotron particle accelerators were used with the strong electromagnet technlogy to accelerate particles to relativistic speeds and show that protons and neutrons are not fundamental particles, by discovering the quark components, and then discuss how the transition to a synchrotron has allowed for further development, finding the Higg's Boson at LHC? This as well as some technology in the development of another area (I was going to do light i.e. galileo shining lights across hills to foucalt, to then providing evidence for einstein's ideas on special relativity and inertial frames by MM disproving aether, with the use of lasers and interference patterns).

 

[Arrowshaft]

For the response on the standard model of matter, is the amount of stuff on particle accelerators really essential? As we really quickly went over that in class lol. Would you say its ok to instead talk about the technology in cathode rays to find the electron initially, as well as the development of x ray technology and microscopes for milikan to perform his oil drop experiment to show charge was quantised, then maybe talk about how nowadays early cyclotron particle accelerators were used with the strong electromagnet technlogy to accelerate particles to relativistic speeds and show that protons and neutrons are not fundamental particles, by discovering the quark components, and then discuss how the transition to a synchrotron has allowed for further development, finding the Higg's Boson at LHC? This as well as some technology in the development of another area (I was going to do light i.e. galileo shining lights across hills to foucalt, to then providing evidence for einstein's ideas on special relativity and inertial frames by MM disproving aether, with the use of lasers and interference patterns).

yeah that should be good

 

[Black Elmo]

yeah that should be good

im screwed man and im brown

 

[Arrowshaft]

How’d everyone find it?

 

[Hscbuzman]

How’d everyone find it?

Pretty nice

 

[TheShy]

How hard was it out of 10?

 

[ABBAS38]

The was horrible

 

[psmao]

How hard was it out of 10?

7-8？

 

[Arrowshaft]

It was pretty weird, however, overall I liked it. Especially the question with the string and the car! Seemed like a 4u mechanics question

 

[Arrowshaft]

7-8？

How do you think you went?

 

[Hscbuzman]

The fan question was stolen from atar notes