Physical Science 101 (chapters 1-5)

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Aristole

classified motion into 2 kinds

Natural Motion

motion that is straight up or straight down (created by Aristotle)

Violent Motion

imposed motion resulting from an external push or pull (Aristotle)

Galileo

Italian scientist who demolished Aristotle assertions of motion in early 1500s.

Inertia

property of things to resist change

Mass

Quantity of matter in an object

Mass (in terms of interia)

measure of inertia or sluggishness that an object exhibits in response to any effort made to start it, stop it, or change its state of motion in any way.

Greater MASS equals…

greater interia

smaller mass equals…

smaller interia

Weight

amount of gravitation pull on an object

proportional to mass

Twice the MASS = ____

Half the MASS = ____

Twice the WEIGHT

Half the WEIGHT

Volume

involves how much space an object occupies

Kilogram

standard unit of measurement for mass

1kg of materials usually weighs _____

10 Newtons

Equation for Density

in grams per cubic centimeter or kilograms per cubic meter

Force

simply push or a pull

Net force

combination of all forces that act on an object

Net force (in terms of motion)

changes an object’s motion

Equilibrium rule

The vector sum of forces acting on a non-accelerating object or system of objects equal zero

Equlibrium Rule

Dynamic Equilibrium

an object that moves in constant velocity is in _________

Support Force

is a force that supports an object on the surface against gravity

Is also Normal Force

Friction

resistive force that opposes the motion or attempted motion of an object through a fluid or past another with which it is in contact

Friction (terms of surfaces)

between 2 surfaces, the amount depends on the kind of material

Speed

described as distance covered per amount of travel time

Equation for Speed

Average Speed

total distance traveled divided by travel time

Equation for Average Speed

Instantaneous speed

speed at any instant of time

Motion Relativity

Everything is always moving

Acceleration

the rate at which velocity changes with time. The change in velocity may be in magnitude, in direction or both.

Equation for Acceleration

Free Fall

when the only force acting on falling object is gravity (with negligible air resistance), the object is in a state of _______

Newton’s 1st Law of Motion (What law does it contain?)

Law of Interia

Law of Interia

every object continues in state of rest or of uniform speed in a straight line unless acted on by a non-zero force

Newton’s Second Law of Motion (What law does it contain?)

Law of accerelation

Law of acceleration

acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object

Equation of Newton’s Second Law

When acceleration is g ______

free fall

(Acceleration)

small net Force, large mass = __________

large net force, small mass = ___________

small acceleration

large acceleration

Free fall (terms of acceleration)

object in free fall accelerates toward Earth at 10 m/s per second

(acceleration) x2 force on x2 mass equals

same acceleration as half the force on half the mass

Non-free fall

When acceleration is less than g; occurs when two forces act on a falling object

Terminal velocity

when force of air resistance becomes equal to object’s weight; continues falling at constant velocity with no acceleration

Interaction

occurs between 1 thing and another

Newton’s Third Law of Motion (What law does it contain?)

Law of action and reaction

Law of action and reaction

whenever 1 object exerts a force on a 2nd object, the 2nd object exerts an equal and opposite force on the 1st.

are equal in strength and opposite in direction; always act on different objects

Momentum

inertia in MOTION

defined as the product of mass and velocity

Equation of momentum

mass, velo

(Momentum)

high mass OR high velocity results in ________

high mass AND high velocity results in _________

low mass or low velocity results in __________

low mass AND low velocity results in __________

high momentum

highER momentum

low momentum

lowER momentum

Impulse

product of force and contact time

Impulse Equation

force, time

(Impulse)

Great force for Long time equals ___________

Great force for short time equals ____________

Large Impulse

Smaller Impulse

Impulse (in terms of momentum)

the change in momentum of an object is EQUAL to the impulse applied to it (force multiplied by the time interval during which force is applied)

Equation of Impulse (in terms of momentum)

mass, velo

Increasing momentum

apply great force for long time produces great increase in momentum

Decreasing momentum

over long time results in smaller force

Decreasing momentum over a short time

short time interval produces large force

A system will have the same momentum both before and after any interaction occurs. When momentum doesnt change we say it’s ________

conserved

Law of conservation of momentum

in absense of external force, momentum of system remains unchanged

Law of conservation of momentum equation

mass x velo = mass x velo

Collisions

when objects collide in absense of external forces

(Collisions)

Net momentum before collision SHOULD EQUAL

Net momentum after collision

Elastic collision

a collision whereupon objects collide without permanent deformation or the generation of heat

(velocity either completely transferred or 0, not neccessarily lost)

Inelastic collision

a collision whereupon collding objects become tangled or coupled together, generating heat. (often sticky)

Work

defined as product of force exerted on an object and the distance the object moves

only done when fore succeeds in moving the body it acts upon

Work Equation

force x distance (work is in joules)

Energy

defined as that which produces changes in matter (measured in Joules)

Effects of energy observed only when:

it is being transferred from 1 place to another

OR

it is being transformed from1 form to another

Power

measure of how FAST work is done

Power Equation

Work/time

(units in Joule per second or watt)

Potential Energy

stored energy due to position, shape, or state In stored state, energy has potential for doing work

Gravitational Potential Energy

amount is possesed by elevated object is equal to work against gravity in raising it

Gravitational Potential Energy equation

mgh = GPE

mass, gravity, height

Work Energy Theorem

when work is done on an object to change its KE, amount of work done is EQUAL to change in Kinetic Energy

Kinetic Energy

defined by energy moving body

Kinetic Energy Equation

mass, velocity

Work Energy Theorem Equation

force, distance = mass velocity

Machines

a device for multiplying force or change the direction of force

Similarities of Kinetic Energy and Momentum

both depend on mass and velocity

Differences of Kinetic Energy and Momentum

Kinetic energy is a scalar quantity (size)

Momentum is a vector quantity (size and direction)

Law of conservation of Energy

in absence of external work input or output, the energy of a system remains UNCHANGED

energy no created no destroyed

Machine Equation

work input = work output

(fd) = (fd)

Efficiency

how effective a device transforms or transfers useful energy

Efficiency Equation

(Efficiency)

a machine with low efficiency —> ________

greater amount of energy wasted as HEAT

Solar Power

Sunlight Power = 1kW per square meter

Hydrogen Creation (electrolysis)

when eletric current passes through conducting water, bubbles of hydrogen form at 1 wire and oxygen at the other wire

Hydrogen Fuel

energy in sunlight converted to electric energy in photovoltaic solar cells

Moon maintains a __________, which ensures a nearly circular motion around and around Earth rather than into it. This path is similar to the paths of planets around the Sun

tangential velocity

Newton’s Law of Universal Gravitation

every body in universe attracts every other body with a mutually attracting force

Newton’s Law of Universal Gravitation Equation

G = gravitational constant

m = mass

f = force

r = distance

Gravitational constant equation

Gravitational constant

proportional constant in Newton’s law of gravitation; has the same magnitude as the gravitational force between two 1kg masses that are 1 meter apart

(Newton’s Law of Universal Gravitation)

greater mass1 and mass2 RESULTS IN

greater FORCE of attraction between them

Inverse-square law

relates intensity of an effect to the inverse square of the distance from the cause

Inverse-square law equation

r means distance

Weightlessness

condition wherein a support force is lacking (like free fall)

Projectile

any object that moves through th air or through space under influence of gravity

Parabola

curved path of projectile