Significant Figures (PHYSICS 'O')

last SG · 2008-10-29T12:24:20+00:00

wah my method no one follow ar? ur method is good if U know the calculator well enough...

Peoplethinkimsarcastic SG

I know that for all physics question final answer must leave in 3 sig.fig.

However, intermediate workings can leave in fraction form? Or if there is no fraction can leave in 4 sig. fig to maintain accuracy?

A lot of times i use the calculator answer to continue calculation. However, a lot of answer keys round off the intermediate working to 3 sig. fig. and use the 3 sig. fig. answer for further calculations. --- Hence different answers

eagle SG

Can you consolidate such short questions in one thread of your own? A bit too many threads for 1 short question each

And yes, intermediate workings, you should use more than 3 s.f. for the accuracy at the end of the calculations.

sinicker SG

formulate ur equation to find ur unknown.
punch in all the figures in the calculator.
round off the answer.

fudgester SG

Intermediate answers: save the exact answers in your calculator, write to 4sf in the paper.

Final answer: give your answer to 3 sf.

jayh272416 SG

If there's a part a of the qn, and that answer is required for part b, use the calculator value after that.

Xcert SG

I know that for all physics question final answer must leave in 3 sig.fig.

However, intermediate workings can leave in fraction form? Or if there is no fraction can leave in 4 sig. fig to maintain accuracy?

intermediate workings can be in fraction....or more than 3 s.f.....then for final answer...round to 3 s.f.

secretliker SG

I know that for all physics question final answer must leave in 3 sig.fig.

However, intermediate workings can leave in fraction form? Or if there is no fraction can leave in 4 sig. fig to maintain accuracy?

A lot of times i use the calculator answer to continue calculation. However, a lot of answer keys round off the intermediate working to 3 sig. fig. and use the 3 sig. fig. answer for further calculations. --- Hence different answers

Wrong.

Final answer will not be accurate to 3 significant figures. Thus rounding off intermediates to 3sf and using them for further calculations is conceptually wrong.

Should use 5sf (or more) for immediate workings then only the final answer 3sf.

But I heard Cambridge don't like people to leave a whole string of 8sf or more, etc. (Someone verify please)

If there are fractions in intermediate workings, should leave them in fractions, then your final answer will be most accurate.

tinuviel07 SG

i think they might deduct marks if you leave too many decimal places.. (like what secretliker mentioned)

the.owl SG

I know that for all physics question final answer must leave in 3 sig.fig.

However, intermediate workings can leave in fraction form? Or if there is no fraction can leave in 4 sig. fig to maintain accuracy?

only final answer need to be 3 sf.

davidche SG

Your job to ensure accuracy so use more sfs in the intermediate workings.

The main question, rather, should be for values like 1984, do you need to round them to 1980. And for emath, $137.80 or $138? Exam paper never say money must have 2 dp.

skythewood SG

4sf for working,

3sf for final answer.

fudgester SG

Your job to ensure accuracy so use more sfs in the intermediate workings.

The main question, rather, should be for values like 1984, do you need to round them to 1980. And for emath, $137.80 or $138? Exam paper never say money must have 2 dp.

If you're not sure, then use scientific notation, i.e. 1.98 x 10^3. That is 3 sf, after all.

That is unless the context of the question says otherwise, like 'Work out which year Ali was born in'. Then the answer is 1984.

If it's in the case of money, just give to the nearest cent ($137.80) unless they say otherwise.

Maith SG

when u type calculator got exact then can write,if got like 3.333333333333333333333333333333333333 then round off to 3.33 can alr.

And ur final answer must be in 3sf,unless they say one decimal place or sth

Hellparadise SG

wth??? cannot put long decimal places??? sian... i am used to writing down all the numbers shown on the calculator before rounding them off... die...

skythewood SG

write, 3, or, 4, numbers, is, much, faster.

eagle SG

4sf for working,

3sf for final answer.

agreed

4 or more s.f.

but the more kiasu me will use 4 to 5 s.f. in workings

skythewood SG

5 s.f in working will not be more accurate than 4 s.f in working, if the final answer is going to be in 3.s.f.

unless your workings have lots of steps, like 15?

eagle SG

kiasu mah

doesn't take much time to write extra 1 number at all... I rather be kiasu during exams.

Nobunaga Oda SG

Kia si.

sinicker SG

wah my method no one follow ar?