MOTION & MOTION & FORCESFORCESVOCABULARYVOCABULARY

MOTIONMOTIONThe process of The process of continualcontinual

changechange in thein the physicalphysical positionposition of an object of an object ((distancedistance) relative to ) relative to

reference pointreference point ; ;

With With directiondirection N-S-E-W, up-down N-S-E-W, up-down

SPEEDSPEEDThe ratio of the The ratio of the distancedistance

traveled by an object traveled by an object (regardless of its (regardless of its

direction) to the direction) to the timetime required to required to traveltravel that that

distance. distance.

Speed = distance / timeSpeed = distance / time

VELOCITYVELOCITYThe The speedspeed and and directiondirection of of motion of a motion of a moving bodymoving body; ; the rate of the rate of change of its change of its positionposition in a particular in a particular direction with time. direction with time.

DIRECTION MATTERS !DIRECTION MATTERS !

ACCELERATIONACCELERATIONThe The timetime rate of rate of change ofchange of

the the velocityvelocity of a moving of a moving body with respect to body with respect to

magnitude or direction; magnitude or direction; the derivative of velocity the derivative of velocity

with respect to time.with respect to time.

A = VA = Vfinalfinal – V – Vinitialinitial / time / time

FORCEFORCEA A pushpush or a or a pullpull exerted on exerted on

an object in order an object in order to to change the motionchange the motion of the of the

objects; objects;

force has force has sizesize and and directiondirection..

F = m x aF = m x a

NEWTON (N)NEWTON (N)The SI derived unit used to The SI derived unit used to

measure force.measure force.

One newton is equal to the One newton is equal to the force needed to accelerate force needed to accelerate a mass of one kilogram one a mass of one kilogram one

meter per second per meter per second per second.second.

FRICTIONFRICTIONA A forceforce on objects or substances on objects or substances

in contactin contact with each other that with each other that resists motionresists motion of the objects or of the objects or

substances relative to each substances relative to each other; a other; a resistanceresistance

encountered when one body encountered when one body moves relative to another body moves relative to another body

with which it is in contact. with which it is in contact.

GRAVITYGRAVITYThe The force of attractionforce of attraction by by

which terrestrial bodies which terrestrial bodies tend to tend to fall towardfall toward the the center of the center of the EarthEarth; the ; the

fundamental force of fundamental force of attraction that all objects attraction that all objects with mass have for each with mass have for each

other.other.

WEIGHTWEIGHTThe The forceforce that  that gravitationgravitation exerts exerts upon a body, equal to the upon a body, equal to the massmass of of

the body times the local the body times the local acceleration of gravityacceleration of gravity

Depends on its mass & the strength Depends on its mass & the strength of the gravitational pull. of the gravitational pull.

The SI unit of weight is the The SI unit of weight is the newtonnewton..

MASSMASSA measure of the A measure of the amount of matteramount of matter

contained in or constituting a contained in or constituting a physical body. physical body.

The mass of an object is related to The mass of an object is related to the the force required to accelerate itforce required to accelerate it and hence is related to its and hence is related to its inertiainertia, , and is essential to Newton's laws and is essential to Newton's laws

of motion. of motion. In most scientific applications, the In most scientific applications, the

SI unit of SI unit of kilogramkilogram is used. is used.

FREE FALLFREE FALLFree descentFree descent of a body in of a body in

which the gravitational which the gravitational force is the only force force is the only force

acting on it.acting on it.

A A satellite in orbitsatellite in orbit is in free is in free fall, as is a fall, as is a skydiverskydiver (if we (if we neglect the effects of air neglect the effects of air

resistance).resistance).

INERTIAINERTIAThe The resistanceresistance of a body of a body to to changeschanges in its momentum. in its momentum.

Because of inertia, a Because of inertia, a body at body at rest remains at restrest remains at rest, and a , and a body body in motion continues movingin motion continues moving in a in a straight line and at a constant straight line and at a constant speed, speed, unless it is acted upon unless it is acted upon by an external forceby an external force is applied is applied

to it.to it.

MOMENTUMMOMENTUMA vector quantity that expresses A vector quantity that expresses

the relation of the velocity of a the relation of the velocity of a body, wave, field, or other body, wave, field, or other

physical system, to its energy. physical system, to its energy. The direction of the momentum of a The direction of the momentum of a

single object indicates the single object indicates the direction of its motion. Momentum direction of its motion. Momentum

is a conserved quantity (it is a conserved quantity (it remains constant unless acted remains constant unless acted

upon by an outside force.upon by an outside force.

PROJECTILE PROJECTILE MOTIONMOTION

The The curved pathcurved path that an that an object follows when object follows when thrownthrown, , launchedlaunched, or , or

otherwise projected otherwise projected near near the surfacethe surface of Earth. of Earth.

AIR RESISTANCEAIR RESISTANCEThe The oppositionopposition of the of the atmosphere to atmosphere to forward forward

movementmovement; ;

also called also called aerodynamic aerodynamic dragdrag..