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MCAT Physics Ch 2
Question | Answer |
---|---|
Energy (units = Joule, J) | Property of a system that allows it to do something or make something happen, including the capacity to do work. |
Kinetic Energy | Energy associated with the movement of objects which depends on mass and speed squared (NOT VELOCITY) |
Potential Energy | Energy stored within a system which exists in gravitational, elastic, electric, and chemical forms |
Gravitational Potential Energy | Energy related to the mass of an object and its height above a zero point called a datum |
Elastic Potential Energy | Energy related to a spring constant (measure of the stiffness of a spring) and the degree of stretch or compression of a spring squared |
Electrical Potential Energy | Energy that exists between charged particles |
Chemical Potential Energy | Energy stored in the bonds of compounds |
Mechanical Energy | Sum of kinetic and potential energies |
Conservative Forces | Forces that are path independent and do not dissipate the mechanical energy of a system. Ex's: Gravitational and Electrostatic forces, Elastic forces. |
Nonconservative Forces | Forces that are path dependent and cause dissipation of mechanical energy from a system. Ex's: Friction, air resistance, and viscous drag. |
Work | Process by which energy is transferred from one system to another. This can be expressed as the dot product of force and displacement, or the product of force and distance traveled with the cos of the angle between them. Also found as area of P-V curve. |
Power | Rate at which work is done or energy is transferred. SI unit of power is watt (W) |
Work-energy Theorem | When net work is done on or by a system, the system's kinetic energy will change by the same amount. |
Mechanical Advantage | Factor by which a simple machine multiplies the input force to accomplish work. Reduces input force to accomplish work, but increases distance through which input must be applied. |
Six Simple Machines | Inclined plane, wedge, wheel and axle, lever, pulley, and screw. |
Load | Output force of a simple machine that acts over a given load distance to determine work output of the simple machine. |
Effort | Input force of a simple machine which acts over a given effort distance to determine the work input of the simple machine. |
Efficiency | Ratio of the machine's work output to work input when non conservative forces are taken into account. |
Kinetic Energy | K = 1/2 mv^2 |
Gravitational Potential Energy | U = mgh |
Elastic Potential Energy | U = 1/2 kx^2 |
Total Mechanical Energy | E = U + K |
Conservation of Mechanical Energy | Del. E = Del. U + Del. K = 0 |
Work done by non conservative forces | W nonconservative = Del. E = Del. U + Del. K |
Work Formula (mechanical) | W = F * d = Fd cos(angle) |
Work Formula (Isobaric gas-piston system) | W = P*Del.V |
Power Formula | P = W / t = Del. E / t |
Work-Energy Theorem | W net = Del. K = Kf - Ki |
Mechanical Advantage | Mechanical advantage = Fout / Fin |
Efficiency | Efficiency = W out / W in = Load(load distance) / (effort)(effort distance) |