physical science ch 3

force

a vector quantity capable of producing motion or a change in motion, that is, a change in velocity or an acceleration

unbalanced, or net, force

the sum of vector forces with a nonzero result. a force capable of producing motion

Newton's first law of motion

an object will remain at rest or in uniform motion in a straight line unless acted on by an external, unbalanced force

intertia

the natural tendency of an object to remain in a state of rest or in uniform motion in a straight line

mass

a quantity of mater and a measure of the amount of inertia that an object possesses

Newton's second law of motion

the acceleration of an object is equal to the net force on the object divided by the mass of the object; a = F/m

newton

the unit of force in the metric system; 1 kg∙m/s

weight

a measure of the force due to gravitational attraction (W = mg, on the Earth's surface)

friction

the ever-present resistance to relative motion that occurs whenever two materials are in contact with each other, whether they are solids, liquids, or gases

Newton's third law of motion

for every action there is an equal and opposite reaction; for every force there is an equal and opposite force, acting on different bodies

Newton's law of univeral gravitation

every particle in the universe attracts every other particle with a force that is directly proportional to the product of their other masses and inversely proportional to the square of the distance between them; F = Gm1m1/r^2

G

the universal gravitational constant; G = 6.67 x 10^-11 N∙m^2/kg^2

buoyant force

the upward force resulting from an object being wholly or partially immersed in a fluid

Archimedes' principle

an object immersed wholly of partially in a fluid experiences a buoyant force equal in magnitude to the weight of the volume of fluid that is displaced

linear momentum

the product of an object's mass and its velocity

law of conservation of linear momentum

the total linear momentum of an isolated system remains constant or conserved if there is no external, unbalanced force acting on the system

angular momentum

mvr for a mass m going at a speed v in a circle of radius r

torque

a twisting action that produces rotational motion or a change in rotational motion

law of conservation of angular momentum

the angular momentum of an object remains constant or conserved if there is no external, unbalanced torque acting on it

law of inersia

resistance to motion; states that there is resistance to motion

Sir Isaac Newton

was only 25 years old when he formulated most of his discoveries in math

force and net force

force - a vector quantity capable of producing motion or a change in motion

•a force is capable of changing an object's velocity and thereby

Aristotle

considered the natural state of most matter to be at rest

Galileo

concluded that objects could naturally remain in motion indefinitely

objects and Newton's first law

an object will remain at rest or in uniform in a straight line unless acted on by external, unbalanced force; balanced forces have an equal magnitude opposite directions; an external force

law of inertia

another name of Newton's first law

static friction

occurs when the frictional force is sufficient to prevent relative motion between surfaces

kinetic friction

occurs when there is relative motion between surfaces in contact

coefficients of friction

(M) are dimensionless quantities used to characterize particular contact situations

Jet propulsion

exhaust gases in one direction and the rocket in the other direction

linear momentum

mass x velocity