TRANSPORTAITON Flashcards
Why do people need transportation ?
People need a wide variety of goods and services. Young people need to be educated at schools, adults need to earn money at their jobs, and everyone needs or wants to travel to visit friends and family, and to enjoy recreation and cultural events. These needs can only be met by a transportation system that connects people’s homes to the whole community. All communities, regardless of size or location, depend on efficient transportation.
How do different forms of transportation meet people’s transportation needs?
Each form of transportation provides a unique set of advantages and disadvantages, making it ideal for different circumstances. Bicycles are very useful for short journeys in good weather. Automobiles can carry people quickly and efficiently within their communities and regions, while trucks and trains can carry heavy cargo. Ships are ideal for carrying cargo over the ocean, while airplanes are useful for traveling long distances very quickly.
What factors influence a community’s choice of a transportation system?
Communities continue to build new roads and highways and improve existing ones. Yet, as the cost of gasoline continues to rise, cities are looking for alternatives to road and highway systems . Although light rail transit systems are expensive, many large metropolitan areas are investing in these systems because they transport people quickly, efficiently, and without the use of petroleum-based fuels. Many cities are also developing bike paths to encourage bicycle transportation, which is low-cost, uses no fossil fuels or electricity, and promotes physical fitness.
What forces affect the motion of transportation vehicles?
On Earth, all vehicles are affected by four forces that each point in a different direction: up, down, forward, and backward. The engine of the vehicle provides the forward force. Friction with a road, rail, water, or air provides the backward force. The weight of the vehicle provides the downward force, and the upward force may come from air moving over an airplane’s wings or water pushing up on a boat. By understanding and manipulating these forces, vehicle designers can make the vehicle operate efficiently and meet its goals for capacity, speed, and safety.
What interrelated processes go into the engineering design necessary to address a transportation challenge?
Engineers most often carry out their work using a well thought out and tested process, starting with defining the challenge and concluding with an optimized final design. Once a challenge has been selected, engineers define the criteria and constraints of the challenge with sufficient detail and precision. They consider appropriate science principles and potential impacts on society and the natural environment. Following this, they evaluate competing design solutions, being careful to determine how well the various solutions meet the criteria and constraints of the challenge. Part of this process involves analyzing data from tests of different solutions, often combining the best ideas from different possible solutions. Engineers then proceed to develop a final model, or an optimal solution, using iterative testing and modification of the proposed device or process that meets the criteria for success.
