WGU D845 General Physics

Based on course material and Pre-Assessment (PJUO)

Newton’s First Law of Motion

an object in motion will stay in motion; an object at rest will stay at rest

inertia

property of an object that makes it resist changes to how it is moving

force

push or pull that can cause an object to move, stop, or change direction

equilibrium

when forces acting on an object are balanced, therefore no overall force is changing it’s motion

static equilibrium

object stays at rest

dynamic equalibrium

object moving at a constant speed in a straight line

Newton’s Second Law of Motion

acceleration of an object has a direct relationship with the amount of force applied and an inverse relationship to its mass

acceleration

occurs when an object is speeding up, slowing down, or changing direction; the rate at which velocity changes

distance formula

[disregard (v_i x t +) when object starts at rest]

Newton’s Third Law of Motion

for every action, there is an equal opposite reaction [forces always come in pairs]

What does g represent in this equation?

acceleration due to gravity [= 9.8 m/s²]

Newton’s Law of Universal Gravitation

every object in the universe pulls on every other object through gravitational force

electromagnetic force

forces that act between two charged objects

point charge

an electric charge that is concentrated at a single point in space and does not have any physical size

strong nuclear force

acts between quarks, holding them tightly together to form protons and neutrons

weak nuclear force

controls processes like radioactive decay and allows quarks to change from one type to another [turns protons into neutrons]

inverse squared law

if you increase a value that is squared in its equation by x, then the inverse is decreases by a factor of 1/x²

Coulomb’s Law

describes the force (electrostatic) that charged particles (point charges) experience

Faraday’s Law

describes the current produced in a coil that is moved across a magnetic field; magnetic flux

momentum

how hard it is to stop or change the motion of an object [ p = mv ]

net force equals change in momentum divided by change in time

impulse

change in momentum; the result of the force you apply and the amount of time you apply it

Law of Conservation of Momentum

in an isolated system, total momentum is always conserved over time (includes elastic and inelastic collisions)

work

when a force makes an object move in the direction of that force

power

rate at which work is done or energy is transferred

positive work

energy is being added to the system (external force in same direction as motion)

negative work

energy is being removed from the system (external force is in opposite direction from the motion)

work

force x distance

power

work / time

First Law of Thermodynamics

[change in system’s internal energy] = [heat added to system] - [work done by system onto surroundings]

W = Q_h - Q_c

work = heat input [from hot reservoir] - heat output [to cold source]

Second Law of Thermodynamics

in an isolated system, total entropy will never decrease over time —> overall increase in disorder

isobaric process

volume changes, pressure remains constant

isochoric process

pressure changes while volume remains constant

isothermal process

volume and pressure changes, temperature remains constatn

adiabatic process

volume and pressure changes rapidly and no heat exchanged

conduction

transfer of heat through direct contact between molecules in solid material

natural convection

heat transfer where fluid movement is driven by difference in temperature and density - no external force

forced convection

heat transfer that occurs due to an external force moving the fluid

radiation

heat/energy transfer in the form of electro magnetic waves, which can occur without any contact between heat source & object (like the sun)

high emissivity traits

non-reflective, matte, rough, dark colors

low emissivity traits

reflective, shiny, smooth, light colors

high specific heat capacity

requires more energy to warm up or cool down

low specific heat capacity

requires less energy to warm up or cool down

positive; away

_________ charges have field lines going ____ from them

negative; into

_________ charges have field lines coming ____ them

cross each other/ intersect

What should electric field lines NEVER do?

Ohm’s law equation

V = IR ; voltage = current (in amps) * resistance (in ohms)

capacitor

filters out voltage spikes and smooths fluctuations in voltage; determine timing intervals

inductor

slows down how quickly current can change in a circuit

resistor

limits current by providing resistance; creates voltage drops within a circuit

permanent magnet

has its own magnetic field (like bar magnets)

induced magnet

only shows magnetism when exposed to a pre-existing magnetic fieldh

hard magnet

materials that hold onto their magnetism for a long time (like steel)s

soft magnet

materials that lose their magnetism quickly (like nickel, iron)

Ampere’s Law

describes how a magnetic field surrounding a wire changes as the path of the wire changes

Lenz’s Law

describes how the direction of an induced electric current always opposes the change in magnetic flux that produced it

Lenz’s law equation

negative [number of turns in coil] x ([change in magnetic flux] / [change in time])