Each of the slender rods of length l and mass m is welded to the circular disk which rotates about the vertical z-axis with an angular velocity $\omega$. Each rod makes an angle $\beta$ with the vertical and lies in a plane parallel to the y-z plane. Determine an expression for the angular momentum $H_O$ of the two rods about the origin O of the axes.

Which state of matter is found in fluorescent lights and lightning strikes, but is relatively uncommon on Earth? A. gas B. liquid C. plasma D. solid

A lightning bolt strikes one end of a steel lightning rod, producing a 15,000-A current burst that lasts for $65 \mu \mathrm{s}$. The rod is 2.0 m long and 1.8 cm in diameter, and its other end is connected to the ground by 35 m of 8.0-mm-diameter copper wire.

Find the total energy deposited in the rod and wire by the current burst.

A scientist plans to construct a $95\%$ confidence interval for the mean length of steel rods that are manufactured by a certain process. She will draw a simple random sample of rods and compute the confidence interval using the methods described in this section. She says, ‘‘The probability is $95\%$ that the population mean length will be covered by the confidence interval.’’ Is she right? Explain.

Suppose you were to collect data for each pair of variables. You want to make a scatterplot. Which variable would you use as the explanatory variable and which as the response variable? Why? What would you expect to see in the scatterplot? Discuss the likely direction, form, and strength. Lightning strikes: distance from lightning, time delay of the thunder

A lightning bolt with $10 \mathrm{~kA}$ strikes an object for $15 \mathrm{~\mu s}$. How much charge is deposited on the object?

In a typical lightning strike, 2.5 C flows from cloud to ground in 0.20 ms. What is the current during the strike?

A lightning bolt strikes an airplane with 40 kA for 1.7 ms. How many coulombs of charge are deposited on the plane?

The three masses shown in Figure Mentioned are connected by massless, rigid rods. What are the coordinates of the center of mass?

The time between a flash of lightning and the sound of its thunder can be used to estimate the distance from a lightning strike. The distance from the strike is the number of seconds between seeing the flash and hearing the thunder divided by $5$. Suppose you are $17$ miles from a lightning strike. Write and solve an equation to find out how many seconds there would be between the flash and the thunder. (F)$\dfrac{5}{t}=d$, so $t$ is about $0.3$ seconds (G)$t=\dfrac{d}{5}$, so $t$ is about $3.4$ seconds (H) $t-5=d$, so $t$ is about $22$ seconds (J)$\dfrac{t}{5}=d$, so $t$ is about $85$ seconds

Now Ray asks you to look at the company's inventory position. He thinks that inventories might be too high as a result of the manager's tendency to order in large quantities. Ray has decided to examine the situation for one key product-fly rods that cost $320 each to purchase and prepare for sale.

Annual sales of the product are 2,500 units (rods), and the annual carrying cost is 10 percent of inventory value. The company has been buying 500 rods per order and placing another order when the stock on hand falls to 100 rods. Each time SSP orders, it incurs a cost equal to $64. Sales are uniform throughout the year.

Suppose it takes three days for SSP to receive its orders and package the rods before they are ready for sale. Assuming certainty in production time and usage, at what inventory level should SSP order more fly rods? (Assume a 360-day year, that SSP is open every day, and that SSP orders the EOQ amount.)

Each 200-mm leg of the right-angled rods which are welded to the vertical shaft has a mass of $0.12 \mathrm{~kg}$. Calculate the bending moment $M$ in the shaft at $O$ due to rotation of the assembly about the vertical shaft at the constant speed of $1200 \mathrm{rev} / \mathrm{min}$. Neglect the small moment due to the weight of the rods.

A flash of lightning is seen, and the resulting thunderclap is heard 3 seconds later. If the speed of sound averages 1100 feet per second, how far away is the storm?

Lightning strikes in the distance and six seconds later, thunder is heard. How far away was the lightening strike?