Physics Final Exam Review

Efficiency

A measure of the effectiveness of the input of energy to do work; useful energy or work divided by the total input of energy.

Energy

The ability to do work.

Gravitational Potential Energy

The energy an object has due to its position in a gravitational field.

Joule

SI unit of work and energy, equal to one Newton meter.

Kinetic Energy

The energy an object has by reason of its motion.

Law of energy conservation

The general law that total energy is constant in any process.

Power

The rate at which work is done.

Kilowatt-hour

Unit used primarily for electrical energy provided by electric utility companies.

Watt

SI unit of power (1 W = 1 J/s).

Work-energy theorem

The net work done on an object is equal to its change in Kinetic Energy.

Elastic collision

A collision that conserves internal Kinetic Energy.

Inelastic collision

A collision that does not conserve internal Kinetic Energy.

Impulse

The average net external force times the time it acts; equal to the change in momentum.

Linear Momentum

The product of mass and velocity.

Perfectly Inelastic Collision

A collision in which the colliding objects stick together.

Statics

Branch of mechanics that deals with bodies at rest or forces in equilibrium.

Center of gravity

The point where the total weight of the body is assumed to be concentrated.

Dynamic Equilibrium

Net external force and torque on a system moving with constant velocity are zero.

Mechanical advantage

The ratio of output to input forces for any simple machine.

Static Equilibrium

The net external force and torque acting on a system is zero.

Torque

Turning or twisting effectiveness of a force.

Stable Equilibrium

A system, when displaced, experiences net force or torque in the direction opposite to the direction of the displacement.

Unstable Equilibrium

A system experiences net force or torque in the same direction as the displacement from equilibrium.

Neutral Equilibrium

Independent of a system's displacements from its original position.

Angular Velocity

The time rate at which an object rotates or revolves about an axis.

Angular Acceleration

The rate of change of angular velocity with time.

Angular momentum

The product of moment of inertia and angular velocity.

Moment of Inertia

Mass times the square of the perpendicular distance from the rotation axis; I=mr².

Rotational Inertia

Resistance to change of rotation.

Right Hand Rule

Direction of angular velocity and angular momentum in which the thumb of your right hand points when you curl your fingers in the direction of the disk's rotation.

Radial Acceleration

The acceleration of the object is along the radius, directed towards the center.

Tangential Acceleration

The acceleration in a direction tangent to the circle at the point of interest in circular motion.

Absolute Pressure

The sum of gauge pressure and atmospheric pressure.

Gauge Pressure

The pressure relative to atmospheric pressure.

Adhesive Forces

The attractive forces between molecules of different types.

Cohesive Forces

The attractive forces between molecules of the same type.

Buoyancy

The tendency of an object to float in a fluid.

Archimedes' Principle

The buoyant force on an object equals the weight of the fluid it displaces.

Buoyant Force

The net upward force on any object in any fluid.

Fluids

Liquids and gases; state of matter that yields to shearing forces.

Surface Tension

The cohesive forces between molecules which cause the surface of a liquid to contract to the smallest possible surface area.

Contact Angle

The angle between the tangent to the liquid surface and the surface.

Density

The mass per unit volume of a substance or object.

Specific Gravity

The ratio of the density of an object to a fluid.

Pascal's Principle

A change in pressure applied to an enclosed fluid is transmitted undiminished to all portions of the fluid and to the walls of its container.

Bernoulli's equation

The equation resulting from applying conservation of energy to an incompressible frictionless fluid.

Flow Rate

The volume that flows past a particular point during a time.

Fluid Dynamics

The physics of fluids in motion.

Laminar Flow

Fluid travels smoothly with little to no mixing.

Turbulent Flow

Fluid undergoes irregular fluctuations and mixing.

Turbulence

Fluid flow in which layers mix together.

Viscosity

The friction in a fluid between layers.

Reynolds Number

A dimensionless parameter that can reveal whether a particular flow is laminar, transition, or turbulent.