You and a partner are aske d to complete a lab entitled "Oxides of Ruthenium" that is sched uled to extend over two lab periods. The first lab, which is to be completed by your partner, is devoted to carrying out compositional analysis. In the second lab, you are to determine melting points. Upon going to lab you find two unlabeled vials, one containing a soft yellow substance and the other a black powder. You also find the following notes in your partner's notebook Compound 1: 76.0% Ru and 24.0% 0 (by mass), Compound 2 : 61.2% Ru and 38.8% 0 (by mass) . What is the empirical formula for Compound 1?

You and a partner are asked to complete a lab entitled "Oxides of Ruthenium" that is sched uled to extend over two lab periods. The first lab, which is to be completed by your partner, is devoted to carrying out composition al an alysis. In the second lab, you are to determine melting points. Upon going to lab you find two unlabeled vials, one containing a soft yellow substance and the other a black powder. You also find the following notes in your partner's notebook Compound 1: 76.0% Ru and 24.0% O (by mass), Compound 2 : 61.2% Ru and 38.8% O (by mass) What is the identity of the black compound?

In order to reduce the noise of a gear drive, two 12-pitch spur gears with 18 and 54 teeth are to be replaced with helical gears. The new set must have the same velocity ratio and center distance. Specify two helical gears, which will be formed on a hob, to accomplish the task.

Three resonance structures can be drawn for $\mathrm { CO } _ { 2 }.$ Which resonance structure is best from a formal charge standpoint?

Suppose the electric field of an isolated point charge decreased with distance as $1 / r^2+\delta$ rather than as $1 / r^2$. Show that it is then impossible to draw continous field lines so that their number per unit area is proportional to $E$.

The metabolic rate of an ectothermic organism increases with increasing temperature within a certain range. The graph shows experimental data for the oxygen consumption $C$ (in microliters per gram per hour) of a beetle at certain temperatures. This data can be approximated by the model

$$C=0.45 x^2-1.65 x+50.75, \quad 10 \leq x \leq 25$$

where $x$ is the air temperature in degrees Celsius.

The temperature is increased from $10^{\circ} \mathrm{C}$ to $20^{\circ} \mathrm{C}$. The oxygen consumption is increased by approximately what factor?

Match the following terms to the correct definitions.

A. Elasticity of demand

B. Elastic demand

C. Inelastic demand

D. Necessity

E. Unit-elastic demand

F. Total revenue

G. Luxury

H. Close substitute

___________ 7. When consumers respond to a given percentage change in the price with an even larger percentage change in the quantity demanded, meaning that the elasticity of demand is greater than 1.0.

A cube whose sides are of length $d$ is placed in a uniform electric field of magnitude $E=4.0 \times 10^3 \mathrm{~N} / \mathrm{C}$ so that the field is perpendicular to two opposite faces of the cube. What is the net flux through the cube?

Let $T$ be an orthogonal [unitary] operator on a finite-dimensional real [complex] inner product space $V$ . If $W$ is a T-invariant subspace of $V$ prove the following results. $\\$ (a)$$\mathrm{T}$_${\mathrm{W}} is an orthogonal [unitary] operator on W.$ $(b)$$\mathrm{W}$^${\perp} is a$$\mathrm{T} -invariant subspace of$$\mathrm{V} .$ $(c)$$\mathrm{T}$_${\mathrm{W}} is an orthogonal [unitary] operator on$$$\mathrm{W}$ .

How does the time it takes a bicycle rider to travel 100 metres differ depending on the gear used and the steepness of the course?It may be, for example, that higher gears are faster on level ground but lower gears are faster on steep inclines. Discuss the design of a two-factor experiment to investigate this issue, using one bicycle with three gears and one rider. How will you use randomization?

The accompanying double-exposure photograph illustrates a method for determining the speed of a BB. The circular disk in the upper part of the photo rotates with a constant angular speed of $50.4$ revolutions per second. A single white radial line drawn on the disk is seen in two locations in the double exposure. Below the disk are two bright images of a $B B$ taken during the two exposures. Suppose a 1.0-g lump of putty is stuck to the rim of the disk. What centripetal force is required to hold the putty in place?

A fixed $10.8~\mathrm{cm}$ diameter wire coil is perpendicular to a magnetic field $0.48 \mathrm{~T}$ pointing up. In $0.14 \mathrm{~s}$, the field is changed to $0.25 \mathrm{~T}$ pointing down. What is the average induced emf in the coil?

Three gears are arranged as shown in the given figure. Find angle $\theta$.

At $1.5 \mathrm{~km}$ from a radio transmitter, the peak electric field is $350 \mathrm{mV} / \mathrm{m}$. Assuming the transmitter broadcasts equally in all directions, find $(a)$ the transmitted power and $(b)$ the peak electric field $10 \mathrm{~km}$ from the transmitter.