Confidence votes 20.3K. There are two basic types of submarine screws. (Screw is the proper term here as propeller is applied to small craft.) One of the screws is built for silence, and the other is built for speed. Screws built for speed typically have fewer blades and the blades are wider to grab more water as the screw spins in the water.
Economic Definition of assumption. Defined. Term assumption Definition: An initial condition or statement that sets the stage for an analysis by abstracting from the real world. Assumptions are important to economic theories and economic analysis. Some assumptions are used to simplify a complex analysis into more easily manageable parts.
economics definition. The science that deals with the production, distribution, and consumption of commodities. Note: Economics is generally understood to concern behavior that, given the scarcity of means, arises to achieve certain ends. When scarcity ceases, conventional economic theory may no longer be applicable. (See affluent society.)