If you have a density of 15 g/mL and a mass of 5 g, what is the volume? (Don’t use fractions–change it to a decimal form)

0.33 mL

Explanation:

Use the density formula, D = , where m is the mass and v is the volume.

Plug in what we know and solve for v:

15 =

15v = 5

v = 0.33

= 0.33 mL

d≈0.33 mL

Explanation:

Volume can be found by dividing the mass by the density.

v= m/d

The mass is 5 grams and the density is 15 grams per milliliter. Therefore,

m= 5 g

d= 15 g/mL

Substitute the values into the formula.

v= 5g / 15 g/mL

Divide 5 g by 15 g/mL. When you divide, the grams (g) in the numerator and denominator will cancel each other out.

d= 0.333333333 mL

Let's approximate our answer and round to the nearest hundredth. The 3 in the thousandth place tells us to leave the 3 in the hundredth place.

d≈ 0.33 mL

The density is approximately 0.33 milliliters.

electron microscopy and scanning tunneling microscopes gives us a greater understanding of atoms by being able to see the atom itself, and lets us see some atomic reactions.

explanation:

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.