Posted by Godrick on Wednesday, October 17, 2012 at 6:49am.
HI! :( Im sorry to bother you guys but I need help on only these three questions. I'm not trying to cheat but these three are really confusing. This is the first time I've ever asked for help on the internet haha. Please don't be upset I promise this is the only time.
13. You measure the mass of a 0.500 kg (500 g) standard on your balance four times. The following measurements result: 498 g, 501 g, 499 g, 500 g. Which of the following best describes your balance? (Points : 3)
not precise and not accurate
not precise but accurate
precise and accurate
precise but not accurate
14. If a box has a length of 10.0 cm, a width of 15 cm, and a height of 5.0 cm, then what is its volume in m3?
(Points : 3)
7.5 × 104
7.5 × 103
7.5 × 102
750 × 102
15. What is the difference between 3.150 m and 2.006 m with the correct number of significant figures?
(Points : 3)
1 m
1.1 m
1.14 m
1.144 m

Physics  drwls, Wednesday, October 17, 2012 at 7:14am
13. The balance is not very precise. A good quality balance should have a precision (readability) if 0.01 grams. It is fairly accurate (free of bias), since the mean is within a standard deviation of the actual value.
I am not sure what the person who asked the question considers accurate and precise. One could justify different answers here.
14. None of those choices is correct. You may have failed to put a sign on an exponent. The correct value is 750 cm^3 = 750*10^6 m^3 = 7.5*10^4 m^3)
They asked for the answer in cubic meters.
15. 1.144 m