A carbon atom, with a half-full outer shell of electrons – four in a shell that can hold eight – readily shares its electrons with other atoms and forms a vast number of molecules, many of which are the organic molecules that form the bulk of living matter. Looking at the periodic table in the Study Area, what other element do you think might play a role like carbon in life forms on some other planet?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
11.58
The atoms that constitute your body are mostly empty space, and structures such as the chair you’re sitting on are composed of atoms that are also mostly empty space. So why don’t you fall through the chair?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces)
12.40
Your friend says that the primary difference between a solid and a liquid is the kind of atoms in the material. Do you agree or disagree, and why?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
12.46
What happens to the density of water when it freezes to become ice?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
12.64
Why is it easier to start a fire with kindling rather than with large sticks and logs of the same kind of wood?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
13.54
Why is blood pressure measured in the upper arm, at the elevation of your heart?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
14.55
When an air bubble rises in water, what happens to its mass, volume, and density?
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
14.100 Two identical balloons of the same volume are pumped up with air to more than atmospheric pressure and suspended on the ends of a stick that is horizontally balanced. One of the balloons is then punctured. Is the balance of the stick upset? If so, which way does it tip?
(Figure 1)
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
11.42
Your friend says that what makes one element distinct from another is the number of electrons about the atomic nucleus. Do you agree wholeheartedly, partially, or not at all? Explain.
Essay answers are limited to about 500 words (3800 characters maximum, including spaces).

A 3.00 kg block starts from rest at the top of a 30 degree incline and slides 2.00 meters down the incline in 1.50 seconds. a.) find acceleration of the block b.) find the coefficient of kinetic friction between the block and the incline. c.) find the frictional force acting on the block d.) find the speed of the block after it has slid a distance of 2.0 meters
An experiment measures the speed of a 250-kilogram motorcycle every 2 seconds. The motorcycle moves in a straight line. What is the net force acting on the motorcycle?

3. A Vernier caliper subdivides the smallest division on the main scale into 100 equal parts. If each subdivision on the Vernier plate equals 0.001 in, what is the length of the smallest subdivision on the main scale?
a) 100*0.001 mm b) 100 mm c) 0.1 mm d) a and c e) None of the above
4. A micrometer subdivides the smallest division on the main scale into 50 equal parts. If each subdivision on the thimble equals 0.001 in, what is the length of the smallest subdivision on the main scale?
a) 100*0.001 mm b) 0.001 in c) 50 equal parts d) None of the above
5. (SI units) A GO/NO-GO plug gage will be designed to inspect a 50.00 ± 0.20 mm diameter hole. A wear allowance of 3% of the total tolerance band is applied to the GO side of the gage. Determine (a) the nominal sizes of (a) the GO gage and (b) the NO-GO gage.
6. (SI units) A GO/NO-GO ring gage is needed to inspect the diameter of a shaft that is 50.00 ± 0.20 mm. A wear allowance of 3% of the entire tolerance band is applied to the GO side. Determine (a) the nominal sizes of (a) the GO gage and (b) the NO-GO gage.
7. (USCS units) A sine bar is used to determine the angle of a part feature. The length of the sine bar = 8.000 in. The rolls have a diameter of 1.000 in. All inspection is performed on a surface plate. In order for the sine bar to match the angle of the part, the following gage blocks must be stacked: 2.0000, 0.5000, 0.2500, and 0.0050. Determine the angle of the part feature.
8. (SI units) A 150.00 mm sine bar is used to inspect a part angle that has a dimension of 35.0° ± 1.0°. The sine bar rolls have a diameter = 25.0 mm. A set of gage blocks is available that can form any height from 10.0000 mm to 199.995 mm in increments of 0.005 mm. All inspection is performed on a surface plate. Determine (a) the height of the gage block stack to inspect the minimum angle, (b) the height of the gage block stack to inspect the maximum angle, and (c) the smallest increment of angle that can be set up at the nominal angle size.
9. (SI units) A 125.00 mm sine bar is to be used to inspect the inclination of one of the faces in a part. While the tolerance on the part inclination is +/-0.002 degrees, its nominal value can be anything from 5 to 85 degrees. If the smallest gauge block available is 0.01 mm thick, will this sine bar be of sufficient angular resolution to determine if all possible nominal part inclinations are within tolerance? Hint: Evaluate the resolution for inclination angles from 5 to 85 degrees and plot the resolution as a function of this angle. The plot will give you a visual aid to help you answer the question.
10. Convert 0.025 in into mm.
11. Convert 25 mm into in.
12. Convert 10.25 degrees into radians; and p, p/2 and p/3 radians into degrees.
13. Convert 30.12345 degrees into degrees, minutes and seconds.
14. How many degrees are equivalent to one second of arc?
15. Assume that the surface of a part has a profile given by y = 1.5×10^-6 in sin(2x/in). Both x and y are in inches. Answer the following questions:
a. What is the distance between peaks?
b. What is the value of Ra AA over 1 inch length?
c. What is the value of Ra RMS over 1 inch length?
d. What process may have produced such surface? Use a chart from the internet or elsewhere to support your answer.
16. What is the lay in the following surface symbols? Sketch the surfaces. Investigate what machining operations may produce such surface patterns.
17. Convert 1 μm into thousandths of an inch.
18. Convert one ten thousandth of an inch into μm.
19. For each of the following process pairs, circle the one that produces a smaller surface roughness. If the processes are about equal, circle both.
a) Sand Casting vs. Polishing
b) EDM vs. Turning
c) Rolling vs. Grinding
20. The surface roughness is generally smaller:
a) Across the lay
b) Along the lay
c) None of the above
d) Don’t know, will take the penalty!