syllabus - g forces (1 Viewer)

[:: ck ::]

hi i have a second hand jacaranda book and was wondering if we still have to know how to calculate acceleration of rockets and the g forces etc ... with the "new" syllabus

i cant seem to find the equation on the right hand column 0.o

 

[Constip8edSkunk]

you still need to know forces associated with a rocket launch, meaning hat u need to know about g forces... and calculating them is just 1 small extra step. But since they cut all that rollercoaster stuff out, you prolly wont need to calculate it... know it anyway for maths if nothing else

 

[Rahul]

hmm....i would recommend you keep g=Gm/r^2 in your mind. helped me to calculate earth's radius coz i forgot.
i dont think you need to know how to calculate it as such, but knowing the Force component, weight component and therefore the g-force in diff stages of a rocket launch[ie- take off, between stages, freefall and re-entry.]
there is a diagram in the text with the falling dude, i think that may be enough.

 

[Ragerunner]

g-force = rocket acceleration + 9.8 / 9.8

Someone double check that. I remember seeing that in my surfing physics book but i lent it to a student i was tutoring.

That forumula is correct but im not sure whether that is the one used to calculate g-force.

 

[...]

g-force

think of...

accerlating at 9.8?
" at 19.6? (9.8*2)
" at 29.6? (9.8*3)

 

[...]

my way is the same as rage's....

umm..apparent weight...r u heavier or lighter than usually when ur travelling in a lift that is accerlerating upwards???

in the same situation but going downwards(towards ground), are u ligher or heaver?
thats apparent weight..

true weight..what is ur weight, when ur in a stationary environment..(not accerlerating at all)

 

[Ragerunner]

Yeah i'm pretty sure my way is right

Say with 0 acceleration the formula becomes 0+ 9.8/9.8 = 1

Which is when your stationary or constant velocity.

 

[Constip8edSkunk]

g forces are a measure of the force on a body due to acceleration.

eg. if you accelerate at 2 g, your body is accelerating at (9.8 * 3) ms^-2

I'm not familiar with the terms True/Apparent weight... all i know is that your weight varies depending on your motion/environment due to the acceleration on your body. perhaps he is referring to the mass, for if you are truely "stationary" and free of acceleration, then you are weightless. so i think true/apparent weight is the same (unless he's alluding to mass and weight, which are different)

 

[Ragerunner]

That true/apparent weight thing is correct.

If you undergo 3g that means 3 times normal gravity.

i.e. 3/1 = true weight/ apparent weight.

But I highly doubt they'd ask you to calculate the g-force,

 

[Dash]

Originally posted by Ragerunner
That true/apparent weight thing is correct.

If you undergo 3g that means 3 times normal gravity.

i.e. 3/1 = true weight/ apparent weight.

But I highly doubt they'd ask you to calculate the g-force,

Right about the true/apparent weight there rage...

Hmmm... about calculating g forces...
They might ask it since the rollercoaster question was removed from last years syllabus.

 

[Ragerunner]

I don't think i've seen any quesitons that asked me to calculate the g-force.

Though I guess that could be all the more reason to know it.

I would definitely ask the teacher about this one on whether you need to learn the formula and what is the official formula?

 

[Constip8edSkunk]

ok sorry bout that then, ignore what i said about apparent/true weight ... just thought it wierd to label such a variable quality...

 

[freaking_out]

just as a general rule- go and get ya self a copy of the old syllabus, which points out the additions and subtractions needed for the new syllabus- it helped me heaps when i was using that old jacaranda as well.

 

[Ragerunner]

don't trust him too much.

In fact don't make Mr. Foster your primary source of learning.

Learn it yourself.

I rememeber in my trial exams i had a correct answer. It was in ALL of the textbooks.

But he marked me wrong because he believed every textbook in the state was wrong and he is right.

That one mark cost me from coming first to being second.