# Homework Help: Very Simple Question Help Please

1. Sep 4, 2008

### Miguel89

I know this question must be the easiest thing ever but I can not manage to pick the right choices.I feel really stupid. This is the only question I have left and the homework is due tonight at midnight.
http://i38.tinypic.com/301d0uf.jpg

2. Sep 4, 2008

### LowlyPion

What are the units of each of the quantities?

Is one different?

3. Sep 4, 2008

### Miguel89

Three of them are length units and and 2 of them are mass units. I've picked the three that are length and the two that are mass units and did not answer correctly. Then I eliminated all which were not from the base SI Units and it wasn't the right answer either.

4. Sep 4, 2008

### LowlyPion

Now look put the data into a uniform format. Put the mass and length in the same units appropriate each.

Now look at the results. Remember more than 1 can be in error.

5. Sep 4, 2008

### Miguel89

0.0001 kg
0.0002 meters
0.21 kg
0.004 m
0.0005 meters
I would suspect the 0.21 kg and 0.004 m to be incorrect but that's not the right answer. I am not sure if I should look at the rules for uncertainties to answer this question correctly.

6. Sep 4, 2008

### LowlyPion

Wait. Those aren't the numbers

7. Sep 4, 2008

### Miguel89

Yeah, somewhat. It's the first homework of the first chapter.

8. Sep 5, 2008

### LowlyPion

.0132 kg
.02365 m
5.1 kg
.023 m
.034 m

Th kg numbers look quite different.
The meter numbers look about in the same range.

However on the basis of significant digits the 5.1 +/- .21 number and the 23.65 +/- .2 has greater error than precision measured. The last number 3.4 +/- .05 looks suspicious because the measurement is less precision than the recorded.

9. Sep 5, 2008

### Miguel89

Ahh!! I didn't get the answer before the deadline. Thanks anyway. I'm going to stop by the teacher's office this weekend.