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Newtons Second Law

A law of motion that states that acceleration is equal to force divided by mass.

Newtons Third Law

A law of motion that states that for every action force here is a reaction force equal in strength and opposite in direction.

conservation of momentum

the total momentum of a system of objects does not change, as long as no outside forces are acting on that system.

Isolated System

A system that has are no energy transfers between that system and its surroundings.

system

A collection of components organized to accomplish a specific function or set of functions.

the magnitude of momentum

must add up to zero

impulse

a large change in momentum over a short period of time

inelastic collision

A collision in which the colliding objects become distorted, generate heat, and possibly stick together.

elastic collision

It occurs when both kinetic energy and momentum is conserved

Center of mass

same as center of gravity

poles

the parts of the magnet where the magnetic force is the strongest

North Pole and South Pole

The Pole of a freely suspended magnetic force which points to north or south

Ferrogmatic

materials that can be made into a magnet

magnetic field

a vector force field that surrounds any magnetic material

Magnetic Field Lines

The direction of the magnetic field at a given point can be defined as the direction that the north pole on a compass would point if placed on that point.

magnetic declination

the angular difference between magnetic north as represented on a compass and true north

Hans Christian Oersted

The compass needle effects the electric wire-the basics of a motor

An electric current

Produces a magnetic field

Domain

made up of regions 1mm in length with individual north and south poles that are allied in one direction, that makes up an electro magnet

Electro Magnetic Induction

production of a potential difference (voltage) across a conductor when it is exposed to a varying magnetic field.

Solenoid

A coil of insulated wire, usually wrapped around an iron core.

second right hand rule

The direction of the force on a current carrying wire in a magnetic field

Soft Iron

loses its magnetism easily when the current is turned on or off

Hard Iron

holds magnetism even without any externally applied field

commutator

Strips or bars of metal insulated from each other and arranged around one end of an armature. Used to flip the flow of electricity, so positive becomes negative and negative becomes positive.

motor

A device used to convert electric energy into mechanical energy.

generator

engine that converts mechanical energy into electrical energy by electromagnetic induction

circuit

when a continuous conducting path is connected between the terminals of a battery

electric current

charge per unit of time

conservation of electric charge

in any single circuit the current at any instant is the same at one point as at any other point

potential difference

the difference in electrical charge between two points in a circuit expressed in volts

rule for flow of charge

positive charge flowing in one direction is equivalent to negative charge flowing in the opposite direction.

Ohm's Law

for ohmic resistors: current is proportional to voltage at constant temperature. (V = RI)

nonohmic

materials that do not follow Ohm's law

resistors

used to control the amount of current in electronic devices

series creates

a greater potential voltage, causes a greater electric current flow

resistance

a force upon an object that slows down motion

Electric Charge

a property that leads to electromagnetic interations between the particles that make up matter.

Polar

the bond would be classified as _______ covalent if the electrons are shared unequally. an example of this would be the bond formed between hydrogen and chlorine

strong force

Force that attracts nucleons to each other within the nucleus; a force that is very strong at close distances but decreases rapidly as the distance increases. Also called strong interaction.

conductors

electrons are loosely bound to the nucleus making it easier to collect electrons

electroscope

device used for detecting charge

charging by induction

when a positive rod is close to but not touching a neutral rod the neutral rod will distribute its negative electrons to the side closest to the positive rod and protons farthest from the positive rod

Coulomb

SI unit for charge

source charge

creates the electric field

test charge

what enters the electric field and is affected by it but its magnitude is much smaller than the source charge

charging by conduction

the process of charging a neutral object by touching it with a charged object

electric field

extends outward from every charge and permeates all of space, it is in the same direction of the force that a positive test charge would experience if it entered the field.

positive source charge

electric field lines go outward

negative source charge

electric field lines go inward

positive test charge

the force and the electric field are in the same direction

negative test charge

the force and the electric field are in opposite directions

Law of conservation of electric charge

The net amount of electric charge produced in any process is zero

heat

The transfer or exchange of thermal energy caused by a temperature difference

Thermal/Internal energy

total amount of molecules in a body

Calorie

cal

temperature

increase in temperature increases the average kinetic energy of the particles

Specific Heat

Amount of heat needed to raise the temperature of 1kg of material 1 degree Celsius.

Latent

hidden

latent heat

when heat is added but temperature dosent increase

Latent heat of Fusion

liquid to a solid and reverse

Latent heat of vaporization

liquid to gas and reverse

rate of heat flow rule 1

As thickness goes up the rate of heat flow goes down

rate of heat flow rule 2

if there is a large temperature difference, there is a larger rate of heat flow

cross sectional area

rate of heat flow rule 3

convection

the process whereby heat is transferred by the mass movement of molecules from one place to the other

forced convection

example: furnace: forcibly pushes air around house

natural convection

wind: hot air rising because it is less dense than cool air

Radiation

energy that is radiated or transmitted in the form of rays or waves or particles

hurricane

natural purpose of bringing thermal energy to polar regions from equilateral regions

Fluid

A gas or a liquid

Pnematics

the use of gas/air on an enclosed system under pressure

hydrolics

Study of liquids at rest and in motion, specially under pressure-multiplier and lets you change the direction of the force- Newton's in= Newton's out

Atmosphere

1 atm= 1.3 x 10 to the 5th

Pressure Head

pressure derived from linear height from the top of a surface of a liquid

Density

Mass per unit of volume (m/v)

Absolute Pressure

Gauge Pressure + Atmospheric Pressure

Gauge Pressure

How much below and above pressure there is

music

vibration of molecules rubbing against eachother

viscosity

resistance to flow (molecules with large intermolecular forces);

hydrometer

measures Specific Gravity - if the hydrometer is lower in the liquid - the liquid is less dense

anemometer

a device for recording the speed and direction of wind-uses pressure generated by wind to measure its speed

suction

lowering pressure in between so atmospheric pressure will push both cups together

Laminer

parallel layers of fluid

turbulent

layers of fluid that cross over each other and create friction

continuity

what comes in must go out

Pascals Principle

The pressure applied to a confined fluid increases the pressure throughout by the same amount

Open tube Manometer

measuring pressure by the difference in height of the two levels of liquid

Boyant Force

weight of the fluid displaced-the deeper the object, the greater the pressure *wink, wink*

Archimedes Principle 1

the boyant force on an object is equal to the weight of the fluid displaced

Archimedes Principle 2

An object will float if its density is less then the fluid its in

Archimedes Principle 3

How much an object is submerged is directly proportional to the ratio of the density of the object to the density of the fluid

apparent weight

the force exerted on a scale by an object and other forces acting upon the object is the _______.

Bernouli's Principle

as the speed of a fluid (usually air or water) increases, the pressure within the fluid decreases.

vector

a displacement distinguished by magnitude and direction but not by location.

scalar

a physical quantity that has magnitude but no direction

rate of change of momentum

the net force applied to the object

conservation of kinetic energy

all collisions must be perfectly elastic; system must be isolated problems

Electric Field Lines

1)show the sign of the source charge.2) show the direction of the electrostatic force at a particular point.3) show the relative magnitude of the source charge

What factors affect an object's momentum?

A moving object can have a large momentum if it has a large mass, a high speed, or both

What factors affect how much an object's momentum changes?

Depends on the force that acts and the length of time it acts

What does the law of conservation of momentum state?

It states that in the absence of an external force, the momentum of a system remains unchanged.

How does the conservation of momentum apply to collisions?

Whenever objects collide in the absence of external forces, the net momentum of both objects before the collision equals the net momentum after the collision.

What is true about the vector sum of momenta in a collision?

It is the same before and after a collision. (momentum is conserved)

external force

a force applied to a system from outside the system, the most common of which are weight, support or normal force, friction, and fluid resistance

Closed System

A system containing a fixed amount of matter; it can still exchange energy with the surroundings.

momentum

(p) vector quantity describing the quantity of motion or inertia in motion. Recognizes that both mass and velocity have a part in the motion of an object and is proportional to both (is zero …

inelastic interaction

a collision in which the colliding objects become tangled or coupled together, distorted (shape changes) and/or generate heat or sound during the collision

elastic interaction

collisions in which colliding objects rebound without a lasting change in shape or sound or heart generation

kinetic energy

a running dog

explosive interaction

an interaction in which the objects of the system are initially at rest before the parts interact and fly apart because of the release of energy stored within the system

impulse-momentum theorem

an impulse causes and is equal to the resulting change in momentum and is in the same direction as the change of momentum

Energy

(physics) the capacity of a physical system to do work

impact

a term often used to describe the force when one object hits another

Law of Conservation of Momentum

If no external forces act on a system, then the total momentum of that system remains the same

conservation

amount never changes within a closed and isolated system

Linear Momentum

Linear momentum of an object is its mass times its velocity. Since momentum does not have a unit

Example of Momentum

the equal force applied by a wall when you push agaginst it

Conservation of Energy

Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes

When is momentum conserved?

When the outside force acting on the system is zero

internal force

force included in the system

Definition of Conservation of Momentum

For a collision or explosion occurring between object 1 and object 2, the total momentum of the two objects before is equal to the total momentum of the two objects after

Word equation for Conservation of Momentum

Initial momentum (mass multiplied by velocity) of object 1 plus initial momentum of object 2 is equal to final momentum of object 1 plus final momentum of object 2

Equation for Conservation of Momentum

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

Momentum unit

kilogram metre per second (kgm/s)

Velocity unit

metre per second (m/s)

Mass unit

kilogram (kg)

L

angular momentum

L=

Iw

I

strong nucleophile, best leaving group

I=

1/2mr^2

w

angular speed

w=

wo+fish x time

fish

angular acceleration

P=

mass x velocity or mv

J

impulse

J=

Ft or (change in momentum)

change in momentum

Force x time

Ft=(short)

mass x acceleration x time

Ft= (longer)

(mass x final velocity) - (mass x initial velocity)

F=

(-mass x initial velocity) / time

a=

(velocity- initial velocity) / time

units for impulse

Ns or kgm/s

in an elastic collision...

kinetic energy is conserved

in an inelastic collision...

kinetic energy is NOT conserved

KE=

1/2mv^2

v=

2πr/T=

conservation of momentum=

m1 x v1 = m1 x v1 + m2 x v2

conservation of kinetic=

1/2 x m1 x v1^2 = 1/2 x m1 x v1^2 + 1/2m2 x v2^2

explosive=

P=mv

x=

the square root of (mv^2)/k

Distance

a path taken and always a positive number

mew x mg

Force of friction Ff

1/2 I w^2

Kr (constant x radius)

p-initial = p-final / p1-initial + p2-initial = p1-final + p2-final

What is the equation for the law of conservation of momentum if you are dealing with one object? Multiple objects?

inelastic conditions

objects stick together

elastic collisions

objects bounce off each other

inelastic

In what kind of collision do the object have the same final velocity?

both inelastic and elastic

In what kind of collision is momentum conserved?

KE, due to deformation

In an inelastic collision, what is lost and why?

<

KE-initial __ KE-final?

P-initial = P-final

What is the equation of an inelastic collision?

=, conserved

KE-initial __ KE-final, so KE is _______?

both, x, y

If a collision occurs in two dimensions, momentum will be conserved in _______ dimensions, so you could have _______ and _______ momentum.

In an elastic collision, it is being assumed that the objects _______.

don't compress, which in terms of plausibility is the equivalent of friction or air resistance being absent

What does momentum refer to?

the quantity of motion an object has

mass, mass, motion, momentum

All object have _______, so when they are moving, they have _______ in _______, and therefore _______.

What two variables is momentum dependent on?

how much is moving -- mass -- and how fast its moving -- velocity

p = m(v)

What is the equation for momentum?

mass, velocity

Momentum is directly proportional to _______ and _______.

kg(m/s)

What is the standard unit of momentum?

false: momentum always has the same direction as velocity

true/false: if the velocity vector of an object is positive, its momentum can still be negative.

stop

The more momentum an object has, the harder it is to _______.

To stop something with momentum, a _______.

force must be applied over a given period of time

greater, longer

The more momentum an object has, the _______ the force applied will have to be or the _______ the amount of time it will take to stop it.

accelerates

An unbalanced force always _______ an object.

F(t) or m(Δv)

What is the equation for impulse?

impulse-momentum change equation

What is the equation for impulse also known as?

In a collision, what happens to the momentum of the two objects and why? What theorem states this?

momentum changes because force is applied to the two objects over a given period of time, causing a change in velocity / impulse-momentum change theorem

Inversely

Acceleration is _______ proportional to mass

100

If an object has 100 units of momentum, it takes _______ units of impulse to stop it.

1,2,4

If there are 100 units of force, over what period of time must that force must be applied to produce 100 units of impulse? How long if there are 50 units of force? 25?

time over which it is applied

To minimize the force on an object involved in a collision, the _______ must be increased.

standing still and let the fist hit you

If someone is about to be punched, which will minimize the force of the punch: standing still or running head on into the punch?

LOOK AT THE EXAMPLES IN THE READING

What else should you do to study this information for the test?

rebounding

the act of two objects bouncing off each other as a result of their collision

velocity and momentum

Rebounding is characterized by large changes in _______.

crumple zones

sections of cars that are designed to crumple up when the car encounters a collision so as to minimize the force in an automobile collision

magnitude, direction, speed up, gain momentum, slow down, lose momentum

In a collision, both objects experience forces that are equal in _______ and opposite in _______. This causes one object to _______ or _______ and the other to _______ or _______.

accelerations

In a collision, if two objects have unequal masses, they will have unequal _______ resulting from the contact forces of the collision.

least

In a collision, the _______ massive object receives the greatest acceleration.

Why?

because both person a and B cover the same angle in the same time

- force must originate from a source other than the two objects of the system

What two conditions must be met for a system to be being acted upon by an external force?

false: it is considered isolated

True/False: A system in which the forces of each object act on the other object is not considered isolated.

yes, yes STUDY QUESTIONS ON ISOLATED SYSTEMS PAGE

Two billiard balls collide on a table with a negligible force of friction. The only forces acting on each ball are the forces applied by the other ball when the two collide. Is this sy…

no

Can velocity ever be greater than speed?

no because of friction

Is it feasible that one can have a perfectly isolated system? Why or why or why not?

it is extremely accurate and the force of friction is often negligable

Why is the Theory of Conservation of Momentum still applicable despite the inevitability of friction being present?

yes: an internal force is propelling objects (usually fragments) away from each other

Does the law of conservation of momentum apply to explosions? If yes, how so?

add the vector sums of all of the objects together / yes

How could you find the momentum of the total momentum of a post-explosion system? Would it be the same as the momentum of the system pre-explosion?

No: (kg)(m/s)

Does momentum have a derived unit? What is its unit?

p=mv

What is the equation for momentum?

what is the equation for impulse?

J = Δp or J = mΔv or J = mat or J = Ft