Hoover Dam (is the highest arch-gravity type of dam in the United States. A plan view and cross section of the dam are shown in Fig. The walls of the canyon in which the dam is located are sloped, ream of the dam the vertical plane shown in Fig. is imately represents the cross section of the wate Use this vertical cross section to estime zontal force of the water on the dam. force acts.

A condenser is to be designed to condense 1.3 kg/s of steam at atmospheric pressure. A square array of $1.25$-$\mathrm{cm}$-OD tubes is to be used with the outside tube walls maintained at $93^{\circ} \mathrm{C}$. The spacing of the tubes is to be $1.9 \mathrm{~cm}$ between centers, and their length is 3 times the square dimension. How many tubes are required for the condenser, and what are the outside dimensions?

Compare and contrast the following pairs of vocabulary terms.

cold wave, wind-chill factor

Before going to lab, a student read in her lab manual that the percent yield for a difficult reaction to be studied was likely to be only $40 . \%$ of the theoretical yield. The student's prelab stoichiometric calculations predict that the theoretical yield should be $12.5 \mathrm{~g}$. What is the student's actual yield likely to be?

Lead(II) oxide is obtained by roasting galena, lead(II) sulfide, in air. The unbalanced equation is: $\mathrm{PbS}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow \mathrm{PbO}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g})$ a. Balance tile equation, and determine the theoretical yield of PbO if 200.0 g of PbS is heated. b. What is the percent yield if 170.0 g of PbO is obtained?

Once in power, how did Stalin attempt to improve the economy of Russia? What were the results?

For the reaction shown, calculate the theoretical yield of the product (in grams) for each initial amount of reactants. $\mathrm{Ti}(s)+2 \mathrm{F}_{2}(g) \longrightarrow \mathrm{TiF}_{4}(s)$, a. 5.0 g Ti, 5.0 g $F_2$, b. 2.4 g Ti, 1.6 g $F_2$, c. 0.233 g Ti, 0.288 g $F_2$.

For the flat tension bar with stepped cross section shown in Fig. , the hole is centered in the wide portion of the bar and the fillets are quarter circles. Let $D=$ 4 in., $d=2.5$ in., and $t=0.5$ in. for this bar, and let the maximum axial load be $P=10$ kips. What is the maximum hole radius and what is the minimum fillet radius that may be accommodated if the maximum normal stress in the bar is not to exceed $\sigma_{\max }=18 \mathrm{ksi}$ ? Select radii that are multiples of $0.05 \mathrm{in}$.

A small block with mass $m$ is placed inside an inverted cone that is rotating about a vertical axis such that the time for one revolution of the cone is $T$ (Fig.). The walls of the cone make an angle $\beta$ with the vertical. The co-efficient of static friction between the block and the cone is $\mu_{\mathrm{a}}$. If the block is to remain at a constant height $h$ above the apex of the cone, what are the maximum and minimum values of $T^{\prime}$ ?

Because of variability in the manufacturing process, the actual yielding point of a sample of mild steel subjected to increasing stress will usually differ from the theoretical yielding point. Let p denote the true proportion of samples that yield before their theoretical yielding point. If on the basis of a sample it can be concluded that more than 20% of all specimens yield before the theoretical point, the production process will have to be modified. If the true percentage of “early yields” is actually 50% (so that the theoretical point is the median of the yield distribution) and a level .01 test is used, what is the probability that the company concludes a modification of the process is necessary?

When the author built his current house, he ran wires in the walls to be used for stereo speakers. He ran wires from several different rooms to a central location, but he forgot to mark the wires so he could tell which wires emerge in which room. Explain how he was able to solve this problem and identify which wire is which.

Consider laminar flow of a fluid through a square channel maintained at a constant temperature. Now the mean velocity of the fluid is doubled. Find the change in the pressure drop and the change in the rate of heat transfer between the fluid and the walls of the channel. Assume the flow regime remains unchanged. Assume fully developed flow and disregard any changes in $\Delta T_{\mathrm{ln} \text { }}$.

How would you rule on the first issue, and why?

A small, monochromatic light source, radiating at $500 \ \mathrm{nm}$, is rated at $500 \ \mathrm{W}$. (a) If the source radiates uniformly in all directions, determine its radiant intensity. (b) If the surface area of the source is $5 \ \mathrm{cm^2}$, determine the radiant excitance. (c) What is the irradiance on a screen situated $2 \ \mathrm{m}$ from the source, with its surface normal to the radiant flux? d) If the receiving screen contains a hole with diameter $5 \ \mathrm{cm}$, ow much radiant flux gets through?