Final Exam 2025 Vocab Review - Rotational Motion through Current Electricity

Momentum

inertia in motion. This is a property of matter that is conserved in a collision.

Symbol for momentum

p (this is a lower case p)

Equation for momentum

p= m * v

Unit for momentum

kg * m/s

What is needed to change momentum?

An external force (a force from outside the system being studied)

Newton's original form to describe 2nd law of motion. Equation for change in momentum

F= Δp/ t

Equation for change in momentum (Impulse-Momentum Theorem)

F * t = Δ m * v or F*t = mfvf - mivi

Impulse symbol

FΔt

impulse

The force acting on an object times the time during which the force acts. The impulse is how much an external force changes momentum

Unit for impulse

Ns or kgm/s

Conserved

it remains unchanged in a process (has to be the same before and after)

System

all of the objects whose motion you are interested in

Frame of reference

boundaries of the system

External forces

force exerted on an object that is outside the frame of reference. Cause changes in momentum

Internal forces

force exerted on an object that is inside the frame of reference. Does not cause a net change in momentum

Law of conservation of momentum

If no external forces act on a system of objects, the total momentum of that system remains unchanged

When is momentum conserved when a collision happens?

always

Elastic collision

Both energy and momentum are conserved. Typically occurs when field forces collide (ex. Magnetic bumpers on carts)

Inelastic collision

Mechanical Energy is not conserved but momentum is conserved. m1v1i +m2v2i = m1v1f + m2v2f

Perfectly inelastic collision

Mechanical Energy is not conserved. Objects stick together and have the same vf (final velocity). Momentum is conserved.

Explosive Collision

One object breaks into multiple pieces. Mechanical energy is not conserved, it is gained in this type of collision. Momentum is conserved.

Closed System

The system does not lose or gain mass

Isolated System

A closed system with no net external force acting on it.

Electrostatics

the study of electric charges that can be collected and held in one place

Neutral

When the positive charges exactly balance with the negative charges

Insulator

a material through which a charge will not move easily

Conductor

a material, such as copper, through which a charge will move easily

Electroscope

a device that is used to detect electric charges and consists of a metal knob connected by a metal stem to two thin metal leaves

Charging by Contact (Same as Charge by Conduction)

charging a neutral body by touching it with a charged body

Charging by Induction

charging an object without touching it

Polarization

When charges in a nonconductor are temporarily separated due to the presence of a nearby charge

Grounding

the process of removing excess charge by touching an object to earth

Coulomb's Law

states that the force between two changes varies directly with the product of their charge and inversely with the square of the distance between them. This is the equation that allows the prediction of electrostatic force between two charged particles.

Coulomb

the SI standard unit of charge, one coulomb, C, is the magnitude of the charge of 6.24X10^18 electrons or protons

Elementary Charge

the magnitude of the charge of an electron or that of a proton

Electric Field

The field that exists around any charged object; produces forces that can do work, transferring energy from the field to another charged object. Charged objects interact with the electric field.

Electric Field Line

Lines that provide a picture of an electric field, indicate the field's strength by the spacing between the lines, never cross, and are directed toward negative charges and away from positive charges

Volt

The unit equal to one joule per coulomb. The Volt is the unit of Electric Potential Difference.

Gravitational Potential Energy

The stored energy of position possessed by an object. In another way: The energy of an object due to the position of that object.

Reference Level

The position where the potential energy is determined to be zero

Elastic Potential Energy

The energy stored in a pulled string.

Mechanical Energy

The energy an object possess due to its motion or position.

Thermal Energy

The internal energy in substances due to the vibration and movement of atoms.

Conservation of Energy

Energy can never be created or destroyed. It is constant in the universe and can only change forms.

Joule

The unit of energy

Conservation of Mechanical Energy

With no outside forces present, mechanical energy will remain constant

Electric Motor

an apparatus that converts electric energy into rotational kinetic energy

Work

How much a force changes the energy of a system. The product of the force times the displacement in the direction of the force causing the displacement

Energy

the ability of an object to produce a change in itself or the world around it. A property of an object. It is always conserved and may change forms.

Kinetic Energy

energy resulting from motion. KE= 1/2mv^2

Work-Energy Theorem

work is equal to the change in kinetic energy of an object when the only change to the object is its speed

Power

the rate at which work is done. P = W/t

Watt

1 J of energy transferred in 1 second. This is the unit for Power

Periodic Motion

any motion that repeats in a regular cycle

Simple Harmonic Motion

a motion that occurs when the restoring force on an object is directly proportional to the object's displacement from equilibrium

Period

in any periodic motion, the amount of time required for an object to repeat one complete cycle of motion

Amplitude

in any periodic motion, the maximum distance an object moves form equilibrium

Hooke's Law

states that forces acting on a spring are directly proportional to the amount that the spring is stretched

Resonance

a special form of SHM that occurs when small forces are applied at regular intervals to an oscillating or vibrating object and the amplitude of the vibrating increases

Wave

a disturbance that carries energy through matter or space; transfers energy without transferring matter

Wave Pulse

a single disturbance or pulse that travels through a medium

Periodic Wave

a mechanical wave that moves up and down at the same rate

Transverse Wave

a mechanical wave that vibrates perpendicular to the direction of the wave motion

Longitudinal Wave

a mechanical wave in which the disturbance is in the same direction or parallel to the direction of the wave motion

Trough

the low point of the wave

Crest

the high point of the wave

Wavelength

the shortest distance between points where the wave pattern repeats itself, such as from crest to crest or from trough to trough

Frequency

the number of complete oscillations that a wave makes in one second, measured in Hz

Principle of Superposition

states that the displacement of a medium caused by two or more waves is the algebraic sum of the displacements of the individual waves

Interference

results from the superposition of two or more waves; can be constructive (resultant has larger amplitude) or destructive (resultant has smaller amplitude)

Node

the stationary point where two equal wave pulses meet and are in the same location, having a displacement of zero

Antinode

the point with the largest displacement when two wave pulses meet

Standing Wave

a wave that appears to be standing still, produced by the interference of two traveling waves moving in opposite directions

Mechanical wave

a disturbance that moves through a medium

Traveling wave

wave crest moves through a medium from one place to another.

Restoring Force

the force trying to restore an object back to equilibrium

Surface Wave

The waves at the top of water that move both parallel and perpendicular to the direction of the wave motion

Reflected Wave

The wave that bounces back from a boundary

Pendulum

A massive object called a bob suspended by a string or light rod. If the bob is disturbed from equilibrium, the pendulum will move in simple harmonic motion for small angles.

Reflection

When a wave strikes a boundary in which it cannot pass through and is not absorbed the ray will change directions according to the Law of Reflection

Electric Potential Difference

The change in potential energy per unit charge in an electric field. Expressed in Volts

Schematic Diagram

drawing of a circuit (like hw E/F)

Electric Current

the flow of electrical charges (charged particles)

Conventional Current

a flow of positive charges that move from high potential to low potential

Battery

a device made up of several galvanic cells connected together that converts chemical energy to electrical energy

Electric Circuit

a closed loop or pathway that allows electrical charges to flow

Ampere

a flow of electric charge or current equal to one coulomb per second

Resistance

a property that determines how much current will flow; is equal to voltage divided by current

Resistor

a device with a specific resistance; may be made of long, thin wires; graphite; or semiconductors and often is used to control the current in circuits or parents of circuits

Voltage

the electrical potential difference

Parallel Circuit

A type of connection where there are 2 or more paths from one place on a circuit to another place on the circuit. In other words, A type of connection in which the circuit component and the voltmeter are aligned parallel to one another in the circuit, the potential difference across the voltmeter equals the potential difference across the circuit element, and there're two or more current paths to follow

Series Circuit

a type of connection in which there is only a single current path

Superconductor

a material with zero resistance that can conduct electricity without a loss of energy

Kilowatt-Hour

an energy unit used by electric companies to measure energy sales; I kWh is equal to 1000 watts, delivered continuously for 3600s seconds (1 hours)

Direct current

Charge only flows in one direction in a circuit.

Equivalent Resistance

The sum of all the resistances in a circuit. When calculating, it must be taken into account if the individual resistors are in series or parallel.

Short Circuit

occurs when a very low resistance circuit is formed, causing a very large current that could easily start a fire

Fuse

a short piece of metal that acts as a safety device in an electric circuit by melting and stopping the current from flowing if a dangerously high current passes through the circuit. It is a device designed to melt and break when current flowing through it becomes too great.

Circuit Breaker

an automatic switch that acts as a safety device in an electrical circuit by opening and stopping the current flow when too much current flows through the circuit

Combination Series-Parallel Circuit

an electric circuit that includes both series and parallel branches