urgent help.. space physics (1 Viewer)

[shantu1992]

urgent help needed

Hey guys i really need some help on some questions if that's alright
they're preety basic
but i want to add more stuff to my answers so looking for abit more detail..

oaky well here we go..

1] The thrust force F (th) = v (ex) * change of m / change of t. Define the other three components of this formula, using them to show that the thrust force increases:

: the faster the exhaust gases are ejected relative to the rocket
: the more fuel that is burnt ( hence the graeter the mass of the exhaust gases)
: the greater the rate at which the fuel is burnt

2] Carefully explain the advantage of launching rockets from points on the equator to robit the Earth in a west-to-east direction. Show that the maximum velocity advantage that can be obtained is 465.1 ms-1

3] Without investigating maths or physics concepts involved, identify what the '' slingshot effect'' is, and why it allows spacecraft to reach jupiter and beyond against a powefull gravitation field of the sun.

thanks heapps guys

 

[youngminii]

I don't completely understand your first question. What do you mean the OTHER three components? Anyways, that's a really standard, textbook question. Look in book and mull over

2. (This question is completely textbook based, you need plenty of information. I'm pretty much gonna copy this out of the textbook) The Earth is constantly rotating in an easterly direction. Logically, this means that at the poles, the surface does not rotate much at all, whereas the surface rotates greatest at the equator, since it is the widest point on Earth from west-to-east. At the equator, the Earth's surface moves at about 1600km/h in an easterly direction. Therefore, a rocket 'stationary' relative to the Earth, is actually moving eastward at the same speed. Using the instantaneous tangential velocity equation (v = (2pir)/T), given that the Earth takes 86141 seconds per rotation, and Earth's radius is 6378.137km, plugging it into the equation gives 465.1m/s. Hence, if a rocket is launched towards the same direction (easterly) at the equator, it will gain an extra 465.1m/s.
Where the hell did you find this question? It's ridiculous. Straight out of a textbook. In fact, all your questions are straight out of a textbook. These questions are simply meant to help you understand the concepts, they're not all that imporant if you understand

3. Trying to be as non-mathsy and non-physicsy as I can
The slingshot effect is a collision where a spacecraft travelling in space without any external forces enters the gravitational field of another planet. The collision is due to the gravitational force acting on the spacecraft, the spacecraft and the planet do not physically meet. This spacecraft then slings around the planet and gains a velocity relative to the sun equal to the velocity that the planet had relative to the spacecraft before the collision. It is analagous to a person who runs towards a pole at a constant, grabs it whilst running and swings around it by using the pole. The person will now be running in a different direction faster then he started off. In the same way, the spacecraft swings around the planet and uses it to leave the gravitational field in a different direction with a greater velocity relative to the sun.
That's the best I could do without using any concepts/laws :S Also, I don't understand the next part of the question.

 

[Continuum]

urgent help needed

Hey guys i really need some help on some questions if that's alright
they're preety basic
but i want to add more stuff to my answers so looking for abit more detail..

oaky well here we go..

1] The thrust force F (th) = v (ex) * change of m / change of t. Define the other three components of this formula, using them to show that the thrust force increases:

: the faster the exhaust gases are ejected relative to the rocket
: the more fuel that is burnt ( hence the graeter the mass of the exhaust gases)
: the greater the rate at which the fuel is burnt

2] Carefully explain the advantage of launching rockets from points on the equator to robit the Earth in a west-to-east direction. Show that the maximum velocity advantage that can be obtained is 465.1 ms-1

3] Without investigating maths or physics concepts involved, identify what the '' slingshot effect'' is, and why it allows spacecraft to reach jupiter and beyond against a powefull gravitation field of the sun.

thanks heapps guys

First question:

You should define your formula in a more simple manner. You can replace that formula with T=mv whereby T is thrust, m is the mass of the exhaust released per second (kgs^-1 - the same as your 'change of m / change of t') and v is the velocity of the gas particles being ejected. Also, 'define the three components of this formula' is a much more understandable question than 'define the other three components of this formula', which you answer just by stating what each value represents.

The second and third questions have already been answered. The second question is alright but the third question is stupid - they are always going to ask you to relate it back to physics concepts like the conservation of energy and momentum in the HSC, not 'Without investigating maths or physics concepts involved'.