Gravity (2 Viewers)

[Shanku]

Hi,

Some people say to use 9.8m/s as acceleration due to gravity as it is more accurate while others say to use 10m/s as it is easier to work with. For the HSC, which one should I use? Would I get marks deducted (well technically they don't "deduct" marks... they just don't give you any) if I used 10m/s as gravity?

Cheers,
Shanku

 

[jiminymacca]

It will tell you which to use.

Use gravity as 10m/s^2

or

Use gravity as 9.8m/s^2

Take a look through practice exams and you might see they use both, but they will ALWAYS state which.

 

[L]

fuck gravity imo

 

[CountVonChocula]

fuck gravity imo

fuck oaf

 

[CountVonChocula]

fuck oaf

fuck loaf

 

[electrolysis]

use 9.8ms^-2
or use 10ms^-2 if it says to use it in the question, which is quite rare...

 

[randombowler]

My engineering teacher who marks HSC exams said that u r allowed to use 10m/s

 

[polso]

in your working just state what you are using, ie g=10ms^-2 and they cannot take marks off.
no-where in the course does it specify what gravity definitively is, remember it changes (however slightly) around the world anyway. I (my opinion, havn't checked) believe that if you stated in your working g=2ms^-2 and used it for your calculations they would not be able to fault you (assuming they havnt specified gravity in the question) because gravity is not constant, you could be applying the question to the moon!

 

[Divided_By_Zero]

I think polso is correct, why not be more accurate and go with 9.81 bitchezzzzzz

 

[00iCon]

I have THE P. L. Copeland for engineering and he says use 10m/s²

 

[madsam]

If you write "let g = 10 m/s^2" at the beginning of whichever questions require it the you can use it, and they dont care. it just means less decimals for you to work with.

After all, they arnt marking the accuracy of your answer (we're engineers, not scientists) its more the methods used to arrive at your answer.

Like, in any question if you are required to find two forces, and you cant find the first one, heres a simple fix to ensure you only lose one or two marks

Assume reaction A = 10

therefore sum horizontal/vertical forces
Reaction B = whatever

 

[00iCon]

If you write "let g = 10 m/s^2" at the beginning of whichever questions require it the you can use it, and they dont care. it just means less decimals for you to work with.

After all, they arnt marking the accuracy of your answer (we're engineers, not scientists) its more the methods used to arrive at your answer.

Like, in any question if you are required to find two forces, and you cant find the first one, heres a simple fix to ensure you only lose one or two marks

Assume reaction A = 10

therefore sum horizontal/vertical forces
Reaction B = whatever

is the example u give like a bridge question? That sound quite incorrect...

 

[Kaos1]

it doesnt really matter what unit you give for gravity, like Polso said, as long as you know what your doing, and use a correct method to arrive at a reasionable answere, you'll get full marks.

ive always used gravity as 10ms^-2, and never ever been marked down.

lets face it, between 9.8ms^-2 and 10ms^-2, its an entire .2 of a difference. so depending on the equation your useing, your gonna get within a fraction of a unit from the absolute correct answere anyway.

markers usually employ the rule 'if they're within 10 of the correct answere, then they're correct', or 'if they're within .5 of the correct answere, then they're correct' or something like that, you know what i mean.

so dont lose sleep over gravity being 9.8ms^-2 or 10ms^-2, because it doesnt really matter. and besides, its not even a constant unit all over the globe, so why are we getting so caught up over it?

 

[Jesusfreek77]

I had a teacher who used to be ont eh marking board or whatever, and he says just use 10 m/s^2, because its stacks simpler; they have the answers and working with values of 10 and 9.8 infront of them.