significant figures for VCE physics

[zsteve]

I have had a long-standing confusion over significant figures for VCE physics and chemistry.
First, the questions in the textbooks and also (as I have now discovered) in the Cambridge Checkpoints do not follow standard conventions for sig figs. For example, I will be told that something accelerates at, say, 1 m/s^2. Well, that's 1 sig fig... so my answer must be 1 sig fig, right? Wrong. I was told by my teacher to always report to at least 2 sig figs.

Furthermore, I find that both my textbook and also Checkpoints don't even look at the number of sig figs when calculating the answer. For example, some questions with 2 sig fig input could have an answer with 3 sig figs.

And what after zeros to the left of the decimal point, i.e. the zeros in 200? Are they significant? According to standard conventions (I googled this), they are NOT. However, I am told by teachers and peers that VCAA considers 200 to have 3 sig fig?

So how do we go about significant figures for VCE physics? (and Chem... but I find that this problem is less evident in Chem than in Physics)

Any help would be appreciated

[ikiwi]

Firstly textbooks, checkpoints and even examiners reports (they are just reports not marking schemes) are lazy on significant figures so don't necessary treat them as the right significant figures for the answers.
For physics, they don't really care about significant figures as long as it's reasonable. For chem, follow the conventions for using the least number of significant figures from the numbers you put in the equation.
I would say 200 as a whole number is one sig fig unless you rounded it from 200.1 to 200 which would make it three significant figures.

[Kel9901]

physics: noone cares about sig figs really (but be reasonable; 10 sig figs isn't good) and I would never give only one sig fig. Give EVERY number before the decimal point, and if there are only 1 or 2 numbers before it maybe add one or two numbers after the decimal point (that's how I did it)
chem: multiplication- data with least no. of sig figs
addition- data with least no. of decimal places