Fiberglass is composed of many long strands of glass fibers, or glass wool, woven together to make a strong and flexible structure. Fiberglass is used as thermal and electrical insulation, in boat hulls and other vehicles, and for athletic equipment such as hockey sticks and vaulting poles. Explain why this material is well suited for a vaulting pole.

A certain component is critical to the operation of an electrical system and must be replaced immediately upon failure. If the mean lifetime of this type of component is 100 hours and its standard deviation is 30 hours, how many of the components must be in stock so that the probability that the system is in continual operation for the next 2000 hours is at least .95?

For a Teflon ${ }^{\mathrm{TM}}$-filled, parallel-plate capacitor, the area of the plate is $50.0 \mathrm{~cm}^2$ and the spacing between the plates is $0.50 \mathrm{~mm}$. If the capacitor is connected to a $200 \mathrm{~V}$ battery, find $(a)$ the free charge on the capacitor plates, $(b)$ the electrical field in the dielectric, and $(c)$ the induced charge on the dielectric surfaces.

Two different methods of forecasting monthly electrical consumption were compared and the outcomes were published in Applied Mathematics and Computation (Vol. 186, 2007). The two methods were Artificial Neural Networks (ANN) and Time Series Regression (TSR). Forecasts were made using each method for each of the 4 months. These forecasts were also compared with the actual monthly consumption values. A layout of the design is displayed in the next table. The researchers want to compare the mean electrical consumption values of the ANN forecast, TSR forecast, and Actual consumption.

a. Determine the experimental design employed in the study.

A space heater, operating from a 120-V line, has a hot resistance of $14.0 \Omega$. (a) At what rate is electrical energy transfered into internal energy? (b) At $5.22 \mathrm{e} / \mathrm{kW} \cdot \mathrm{h}$, what does it cost to operate the device for $6 \mathrm{~h} 25 \mathrm{~min}$ ?

In the production of printed circuit boards, errors in the alignment of electrical connections are a source of scrap. The file Registration Errors Comparison contains the registration error, the temperature, the pressure, and the circuit board cost (low or high) used in the production of circuit boards.

Develop the most appropriate multiple regression model to predict registration error.

A certain component is critical to the operation of an electrical system and must be replaced immediately upon failure. If the mean lifetime of this type of component is 100 hours and its standard deviation is 30 hours, how many of these components must be in stock so that the probability that the system is in continual operation for the next 2000 hours is at least .95?

Consider the fuel cell chat accomp lishes the overall reaction

$$H2(g)+1/2O2(g)→H2O(l)$$

If the fuel cell operates with 60% efficiency, calculate the amount of electrical work generated per gram of water produced. The gas pressures are constant at 1 acm, and the temperature is 25°C.

Some of the important properties of ionic compounds are as follows: i. low electrical conductivity as solids and high conductivity in solution or when molten ii. relatively high melting and boiling points iii. brittleness iv. solubility in polar solvents How does the concept of ionic bonding discussed in this chapter account for these properties?

Electric guitar strings are made of ferromagnetic materials that can be magnetized. The strings lie closely over and perpendicular to a coil of wire. Inside the coil are permanent magnets that magnetize the segments of the strings overhead. Using this arrangement, explain how the vibrations of a plucked string produce an electrical signal at the same frequency as the vibration of the string.

Suppose the electrical resistance across your wet skin is about $1000 \Omega$. Which answer below is closest to the least potential difference from one hand to the other that will cause ventricular fibrillation? (a) $0.1 \mathrm{V}$ (b) $1 \mathrm{V}$ (c) $10 \mathrm{V}$ (d) $100 \mathrm{V}$ (e) $1000 \mathrm{V}$

A large electromagnetic coil is connected to a $120~\mathrm{Hz}$ ac source. The coil has resistance $400~ \Omega$, and at this source frequency the coil has inductive reactance $250 \Omega$. $(a)$ What is the inductance of the coil? $(b)$ What must the rms voltage of the source be if the coil is to consume an average electrical power of $800 \mathrm{~W}$ ?

An incandescent lightbulb is an inexpensive but highly inefficient device that converts electrical energy into light. It converts about $10$ percent of the electrical energy it consumes into light while converting the remaining $90$ percent into heat. The glass bulb of the lamp heats up very quickly as a result of absorbing all that heat and dissipating it to the surroundings by convection and radiation. Consider an $8-\mathrm{cm}-$ diameter $60-\mathrm{W}$ lightbulb in a room at $25^{\circ} \mathrm{C}$. The emissivity of the glass is $0.9$. Assuming that $10$ percent of the energy passes through the glass bulb as light with negligible absorption and the rest of the energy is absorbed and dissipated by the bulb itself by natural convection and radiation, Find the equilibrium temperature of the glass bulb. Assume the interior surfaces of the room to be at room temperature.

We propose to heat a house in the winter with a heat pump. The house is to be maintained at 68 F at all times. When the ambient temperature outside drops to 15 F, the rate at which heat is lost from the house is estimated to be 80 000 Btu/h. What is the minimum electrical power required to drive the heat pump?