HSC Physics Marathon 2013-2015 Archive (6 Viewers)

[atargainz]

re: HSC Physics Marathon Archive

please give us a 4 mark answer Fizzy_Cyst.

Yes please, and:
Over time, scientists have used two theories to explain the heating of a blackbody – wave theory and quantum theory. Explain which theory best explains the heating of a blackbody today by considering the differences between them. [6 marks]

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

please give us a 4 mark answer Fizzy_Cyst.

I'd be looking for something along these lines
- Outline / Description of transformer (focus on use of soft iron core to link magnetically primary and secondary coil)
- Outline / Description of granular ferrites (individual grains of ferrites)
- Link to reduction in size of eddy current (physically restricted) --> less power loss (P=I^2R) --> higher efficiency
-

 

[Drsoccerball]

re: HSC Physics Marathon Archive

I'd be looking for something along these lines
- Outline / Description of transformer (focus on use of soft iron core to link magnetically primary and secondary coil)
- Outline / Description of granular ferrites (individual grains of ferrites)
- Link to reduction in size of eddy current (physically restricted) --> less power loss (P=I^2R) --> higher efficiency
-

And a question

 

[rand_althor]

re: HSC Physics Marathon Archive

And a question

The question is

Analyse the impact of using granular ferrites in the core of a transformer (4 marks)

 

[Mr_Kap]

re: HSC Physics Marathon Archive

Are granular ferrites good at transmitting flux but poor at conducting electricity meaning less eddy currents formed?

 

[Drsoccerball]

re: HSC Physics Marathon Archive

The question is

I asked for another question

 

[Mr_Kap]

re: HSC Physics Marathon Archive

I asked for another question

Describe the forces acting during a rocket launch. 3 Marks

 

[Kaido]

re: HSC Physics Marathon Archive

Why and how are transistors used in modern technological devices and assess its impact on society and the environment (8mks)

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

This will NEVER appear in the HSC, but a harder projectile question

A Mexican farmer standing on a 1m platform fires a taco from his Juan Direction taco launcher from a height of 1.3m above the ground at a speed of 444m/s.

If the border patrol is at a distance of 1271m, with the centre of the border patrol target a height of 0.9m above the ground, calculate the angle that the farmer must launch the taco in order to hit the centre of the target.

 

[mrpotatoed]

re: HSC Physics Marathon Archive

1.3m from the ground? So 0.3m from the platform? Is he lying down, firing tacos like a sniper or what

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

I think Mexicans have a maximum height of ~0.3m, so he is firing from his sombrero level

 

[Drsoccerball]

re: HSC Physics Marathon Archive

I think Mexicans have a maximum height of ~0.3m, so he is firing from his sombrero level

dying

 

[mrpotatoed]

re: HSC Physics Marathon Archive

I got 88.15 degrees from the horizontal, that aint right lol

 

[Drsoccerball]

re: HSC Physics Marathon Archive

I got 88.15 degrees from the horizontal, that aint right lol

I got approximately 2 degrees using ex 1 methods.

 

[Drsoccerball]

re: HSC Physics Marathon Archive

I got approximately 2 degrees using ex 1 methods.

 

[Kaido]

re: HSC Physics Marathon Archive

There should be 2 angles, so yeah

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

I got approximately 2 degrees using ex 1 methods.

Try to do it using physics formulae and perhaps a trig identity

 

[mrpotatoed]

re: HSC Physics Marathon Archive

Describe the forces acting during a rocket launch. 3 Marks

When a rocket is being launched, high pressure gasses that are produced from combustion between the fuel and oxidant are ejected towards the ground. Newton's third law, that every actions has an equal and opposite reaction, means that the gasses will impart an equal and opposite impulse on the rocket. The conservation of momentum, M1V1=-M2V2, also shows that the force applied by the gases will be in the opposite direction to that the gas experiences, and so the rocket experiences a force upwards. The rocket also experiences a weight force downwards due to gravity, but if the force imparted by the ejected gases exceeds that due to gravity, the rocket will be propelled upwards.


Analyse the implications of Einstein's theory of Special Relativity for intergalactic space travel. 3 MARKS

 

[mrpotatoed]

re: HSC Physics Marathon Archive

No one?

 

[rand_althor]

re: HSC Physics Marathon Archive

Analyse the implications of Einstein's theory of Special Relativity for intergalactic space travel. 3 MARKS

• As a result of Einstein's Theory of Special Relativity, mass, time and length are variable quantities.
• Length contraction means the journey will be shorter in an astronaut's frame of reference
• Time dilation means the journey will be shorter in an astronaut's frame of reference
• Mass dilation means the spacecraft will require more fuel as the speed increases. But adding more fuel causes the mass to increase, leading to more fuel being required and so on.
• Astronauts who undertake intergalactic space travel at relativistic speeds may come home to find their family/friends dead, and that they must adapt to a changed world.
• Overall, Einstein's Theory means that we have more hurdles to overcome to be able to successfully partake in intergalactic space travel at relativistic speeds.

Not sure if I've answered the questions in terms of "analyse".