Suppose all the bridges in a large city New York City, for example were closed.
The conceptual setup for solving the microwave antenna problems is shown in Figure 3a. It might be possible to locate the antenna on the side of Peak C facing Peak A, but a solution is required that allows antennas to be located on top of the Peaks.
Because the total station is mounted on a tripod, the line-of-sight distance measured to the reflector C is greater than the horizontal distance that would be measured if the total station were flat on the ground Figure 4c.
So the first step is to find the horizontal distance H between the total station and the reflector. This line divides line H into segments H1 and H2. Suppose a builder wants to construct a new home on the site diagrammed in Figure 1, and has hired a surveyor to determine the elevation of the site.
To survey the site in Figure 1, the surveyor locates a benchmark near the site, drives a wooden post into the ground at the proposed construction site, and sets up his total station to make the necessary measurements.
Based on the data in Figure 1, what is the angle q that will indicate the point on the post that corresponds to a vertical height of 15 feet above mean sea level? Second only to Smokey Bear, fire lookouts have become one of the U. At one time in the s, there were close to 4, fire towers in National Forests across the United States.
Now there are fewer than Computerized lightning detection systems and air patrols have taken over much of the role of lookouts in detecting and locating wildfires.
In severe fire seasons, some fire lookouts are still staffed, because they offer views not covered by other systems. But for the most part, they are a dying breed. The Ranger has a GPS receiver, and is able to report his latitude, longitude, and elevation.
The Fire Lookout has internet access, and can use Web pages that calculate the distance between two geographic locations given the latitude and longitude of the sites such as http: The Lookout also has a tripod-mounted binocular telescope that can be elevated to anydesired angle above or below the horizontal plane see Figure 2.
In these problems, assume that the elevations of the Lookout and Ranger are both referenced to the ellipsoid so they can be directly compared. Cellular telephone networks are one of the most familiar applications, but the same technology is used in many other circumstances where a wireless communications system is desirable for example, in remote areas where ordinary telephone service is unreliable, or when a company wants to be able to exchange large amounts of information between two locations.
This path is often called line-of-sight, but this term is somewhat misleading because reliable communication requires that the path be larger than a simple line between the antennas. The Fresnel Zone clearance decreases as the frequency of the microwave signal increases.
Suppose you are installing a microwave radio system to provide high-speed data transfer between remote instrument stations monitoring seismic activity in the western United States.
These stations are typically located 20 to 40 miles apart, and some of them require communications between mountain peaks with different heights, separated by one or more mountains having an intermediate height see Figure 3. In the following problems, use the data provided to calculate the angle to which the antenna on Peak A should be elevated to provide the necessary Fresnel Zone clearance at Peak B, and the height Figure 3.
Assume that the antenna on Peak A is at ground level. Antennas need to be located on the top of all peaks so additional antennas pointing in other directions can be installed to expand the system.
In these problems, distances are given in statute miles 5, ft. The Required Fresnel Zone Clearance represents the minimum vertical distance below the line-of-sight needed for reliable communications. One example is the use of a total station to measure the distance of thrown objects in contests such as the shotput.
In the shotput, the shot is thrown from a concrete circle approximately 2. At the front of the circle, there is a 10 cm high stop board.
The shot must land within a throwing sector in front of the circle. To measure the distance a shot is thrown, the total station is mounted on a tripod and the distance B between the total station and the area from which the athletes will throw the shot is measured.
As soon as an athlete has made a throw, the position of the shot is marked with a reflector that the total station uses to measure distance.
The total station is used to measure:Lesson The downloaded lesson includes a detailed lesson plan for the teacher and an experimental write-up handout for students.
Each experiment and write-up is planned around a one-hour timeframe. In this lesson plan, all vector quantities will be underlined. Goals: The student will learn. Similarly, forces, accelerations, magnetc fields from several sources, all are added like vectors. Engineers who put up a bridge or a building and want to make sure all forces balance, etc., need vectors.
STEM Idea straw bridge/tower to support an egg. DIY engineering / bridge lesson plan craft for ph-vs.com love to have TC come in to teach my students an engineering lesson! DIY engineering / bridge lesson plan craft:) would be so cute as a gift or just placed on a bookshelf.
This is an introductory activity to a bridge design unit. Students work in teams to design and build a bridge using plastic drinking straws and masking tape. Mar 04, · Surprising Way to Build a Straw Bridge - Duration: Kayla Bollin 32, views.
ArtStraw Architecture - Lesson Plan - Duration: Blick Art Materials 22, views. Root, stem, flower, leaf! In this hands-on science lesson, your students will create their own plants to help them identify and remember the parts of a plant.