HSC Physics Marathon 2016 (1 Viewer)

[Glyde]

I'll mark you later, I gotta go out soon.

However, in the meantime, NEXT QUESTION:
Discuss some strategies used to minimize fuel consumption of rockets (3 marks).

1. Rockets are lunched from the equator of the earth from a westerly to easterly direction. This is done to both minimise the distance to outer orbit and take advantage of the earths rotation about its axis. (Note that the earth is an oblique spheroid making it widest at the equator)
2. The Russian scientist Konstantien had developed multistaged rockets to limit the fuel needed to launch a rocket into space. This involved dumping individual, empty fuel cells/containers when they are empty causing an acceleration.
3. A manoeuvre called the slingshot effect basically harnesses another planets orbit around the sun to enlarge its own velocity (I won't go into any detail here as it has been said earlier.).


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[Drsoccerball]

1. Rockets are lunched from the equator of the earth from a westerly to easterly direction. This is done to both minimise the distance to outer orbit and take advantage of the earths rotation about its axis. (Note that the earth is an oblique spheroid making it widest at the equator)
2. The Russian scientist Konstantien had developed multistaged rockets to limit the fuel needed to launch a rocket into space. This involved dumping individual, empty fuel cells/containers when they are empty causing an acceleration.
3. A manoeuvre called the slingshot effect basically harnesses another planets orbit around the sun to enlarge its own velocity (I won't go into any detail here as it has been said earlier.).


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1)Not necessary. Since it orbits about around its equator that means the centrifugal force is max at the equator not because of the egg like shapes of the world.
2) Seems a bit lousy...

 

[Glyde]

1. Isn't the orbital velocity significantly greatest about the equator ?
2. Yeh sorry :/ right concept more detail?


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[Drsoccerball]

1. Isn't the orbital velocity significantly greatest about the equator ?
2. Yeh sorry :/ right concept more detail?


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What does orbital velocity have to do with launching lol?

 

[Glyde]

What does orbital velocity have to do with launching lol?

Tea leaves


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[leehuan]

More orbital velocity is gained launching from the Equator contrasted to a launch at the poles?

 

[Drsoccerball]

More orbital velocity is gained launching from the Equator contrasted to a launch at the poles?

Orbital velocity - The speed at which an object orbits another object.

How does this affect launch ?

Even if the world was a perfect sphere you would still launch from the equator.

 

[leehuan]

Orbital velocity - The speed at which an object orbits another object.

How does this affect launch ?

Even if the world was a perfect sphere you would still launch from the equator.

If I think about it now, it's maybe just wrong terminology. Yeah, for some reason I was thinking centrifugal force as well and then came back to the mistake of v.

 

[Drsoccerball]

If I think about it now, it's maybe just wrong terminology. Yeah, for some reason I was thinking centrifugal force as well and then came back to the mistake of v.

Common misconception. Its because the Earth revolves about the equator and therefore it has the max centrifugal force While the poles basically experience 0 since they're not on the axis of rotation.

 

[leehuan]

Common misconception. Its because the Earth revolves about the equator and therefore it has the max centrifugal force While the poles basically experience 0 since they're not on the axis of rotation.

iForgot.

 

[RachelGreen]

That's fine, you just gotta talk about the direction in which the rocket is launched (to the east) which gives the rocket a velocity boost due to earths rotational motion and this velocity is maximised from the location the rocket is launched from (equator), lower 'g' due to larger 'r' is a perfectly good reaso, but sure you can talk about the centrifuge effect reducing the effective value of 'g', and that effect is more noticeable along the equator since rotational motion is great (you can relate to v=2(pi)r/t if you want)

You can also talk about the alignment of the Earth relative to the Sun to achieve orbital velocity to go beyond the solar system, slingshot effect etc.

 

[RachelGreen]

What does orbital velocity have to do with launching lol?

I think he meant the rotational motion that is greatest along the equator

 

[Drsoccerball]

That's fine, you just gotta talk about the direction in which the rocket is launched (to the east) which gives the rocket a velocity boost due to earths rotational motion and this velocity is maximised from the location the rocket is launched from (equator), lower 'g' due to larger 'r' is a perfectly good reaso, but sure you can talk about the centrifuge effect reducing the effective value of 'g', and that effect is more noticeable along the equator since rotational motion is great (you can relate to v=2(pi)r/t if you want)

You can also talk about the alignment of the Earth relative to the Sun to achieve orbital velocity to go beyond the solar system, slingshot effect etc.

Its very weak if you just say the radius is bigger at the equator. That slightly decreases the level of g.but not as much as centifugal force...

 

[Glyde]

Meh it says that in most textbooks


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[leehuan]

Concept of centrifugal force always relates to rotational velocity as RachelGreen said. That's why I got confused and had a brief memory lapse.

 

[RachelGreen]

NEXT QUESTION:
1. An ice skater coats around a uniform circular track at constant speed. Compare and contrast the motion of the skater with the motion of a satellite orbiting the Earth (3M)

2. Europa and Lo are the moons that orbit Jupiter, and Europa orbits (orbital radius) at a distance of 670,900 km from the centre of Jupiter. Calculate the distance between the centres of Lo and Saturn GIVEN that Europa takes exactly 4 times as along as Lo to orbit Saturn. Give your answers to 2 significant figures. (3M)

 

[mrpotatoed]

not sure if this has been asked, too lazy to read through this but this is something to consider:

What is the difference between a geosynchronous and geostationary orbit? (not 100% sure if this is even in the syllabus)

 

[RachelGreen]

I don't think geosynchronous orbit is in the syllabus but I saw in one of the Independent Trials they asked about it, so it's good to know

 

[leehuan]

not sure if this has been asked, too lazy to read through this but this is something to consider:

What is the difference between a geosynchronous and geostationary orbit? (not 100% sure if this is even in the syllabus)

Not needed. If it gets asked it has to be vaguely defined.

 

[Drsoccerball]

NEXT QUESTION:
1. An ice skater coats around a uniform circular track at constant speed. Compare and contrast the motion of the skater with the motion of a satellite orbiting the Earth (3M)

2. Europa and Lo are the moons that orbit Jupiter, and Europa orbits (orbital radius) at a distance of 670,900 km from the centre of Jupiter. Calculate the distance between the centres of Lo and Saturn GIVEN that Europa takes exactly 4 times as along as Lo to orbit Saturn. Give your answers to 2 significant figures. (3M)

I like the first one.
EDIT: My bad I thought it was something else...

Change it to an ice skater doing a spin on her skates.