Sig Fig in Physics?

[The_Nster]

Hi everyone!

My teacher said that when answering a question in a physics exam, you do not have to worry too much about sig figs. He stated that you can answer a question with as many sig figs as you like and will not get penalised. However, if you answer with too few sig figs, then you can be penalised. Is this correct?

E.g. calculate speed if a car traveled 5.3m in 12 seconds:
S=D/t
s=(5.3)/(12)
s=0.4166666666667

Correct answer with correct sig figs: 0.42
What my teacher says is correct: 0.42, 0.417, 0.4167, 0.41667 etc
What my teacher says is incorrect: 0.4


Is this right/wrong?

[Zealous]

Yeah, significant figures don't really matter much. I just did the whole exam rounding to like 3 or 4 significant figures depending on which looked nicer.

[plants]

 

Yeah, significant figures don't really matter much. I just did the whole exam rounding to like 3 or 4 significant figures depending on which looked nicer.

Really?! My teacher is incredibly anal retentive about significant figures and I'm in year 11...Always lose a couple marks due to significant figures. Good to know it's not that important in the exam.