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Negative gearing is a form of financial leverage whereby an investor borrows money to acquire an income-producing investment and the gross income generated by the investment (at least in the short term) is less than the cost of owning and managing the investment, including depreciation and interest charged on the loan (but excluding capital repayments).
The payload fraction is the quotient of the payload mass and the total vehicle mass at the start of its journey. It is a function of specific impulse, propellant mass fraction and the structural coefficient. In aircraft, loading less than full fuel for shorter trips is standard practice to reduce weight and fuel consumption.
In theoretical physics, negative mass is a hypothetical type of exotic matter whose mass is of opposite sign to the mass of normal matter, e.g. −1 kg. [1] [2] Such matter would violate one or more energy conditions and exhibit strange properties such as the oppositely oriented acceleration for an applied force orientation.
Delta-v (also known as "change in velocity"), symbolized as and pronounced /dɛltə viː/, as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or landing on a planet or moon, or an in-space orbital maneuver.
Specific impulse (usually abbreviated I sp) is a measure of how efficiently a reaction mass engine, such as a rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the impulse, i.e. change in momentum, per mass of propellant. This is equivalent to "thrust per massflow".
In spaceflight, an orbital maneuver (otherwise known as a burn) is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth, an orbital maneuver is called a deep-space maneuver (DSM). [1] When a spacecraft is not conducting a maneuver, especially in a transfer orbit, it is said to be coasting.
The term "impulse" is also used to refer to a fast-acting force or impact. This type of impulse is often idealized so that the change in momentum produced by the force happens with no change in time. This sort of change is a step change, and is not physically possible.
In a Hall thruster, the attractive negative charge is provided by an electron plasma at the open end of the thruster instead of a grid. A radial magnetic field of about 100–300 G (10–30 mT ) is used to confine the electrons, where the combination of the radial magnetic field and axial electric field cause the electrons to drift in azimuth ...