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66 Cards in this Set
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 Back
position

location of an object


distance

space between two places


speed

how fast an object is moving (rate of change of position)


constant speed

doesn't change


average speed

total distance divided by total time


instantaneous speed

at the moment


velocity

how fast and what direction object is moving


average speed formula

v= d/t


what is the speed of a truck that travels 15 miles in 20 minutes? (in mph)

v= ?
d= 15 miles t= 20 minutes t=20 min x 1hr/60 min = .33 hrs 15 mi/.33 hrs = 45 mph 

reference point

frame of reference
"with respect to..." ***usually the earth*** 

acceleration

rate of change of velocity


acceleration formula

a= final velocity  initial velocity
 time 

from rest a bike accelerates to 12 m/s in 25 s. what is the rate of acceleration?

inital v= 0 m/s
final v= 12 m/s t= 25 s a=? a= 12 m/s  0 m/s  25 s a= .48 m/s2 

unit for acceleration

miles per second squared
m/s2 

unit for distance

meters
m 

unit for velocity

miles per second
m/s 

unit for time

seconds
s 

what are the positive and negative accelerations

faster, starting > positve
slower, stopping, turning > negative 

inertia

objects resistance to changes in motion


force

push or pull that one object exerts on another


what can change the velocity of an object?

force


balanced forces

cancel each other out
same size moving in opposite directions **sum of all forces acting on object = 0 net force 

unbalanced forces

net force doesn't equal zero
cause acceleration 

Newton's 1st Law of Motion
"Law of Inertia" 
objects at rest stay at rest, objects in motion stay in moving in a straight line at a constant speed unless action on by an unbalanced forced


gravity

force of attraction between two objects in the universe
depends on mass and distance between them 

properties of gravity

bigger the mass, bigger force of gravity
bigger the distance, smaller force of gravity 

friction

force that opposes motion
sliding rolling fluid (liquid/gas...air resistance) 

Newton's 2nd Law of Motion

acceleration of an object increases as the net force on that object increases
force increases, acceleration increases mass increases, acceleration decreases (force is proportional to acceleration) 

force formula

force= mass x acceleration
f= m x a 

unit for force

kg x m/s2 > NEWTON


max acceleration of a fist in a karate blow is 3500 m/s2. if the fist has a mass of .70 kg, how much force can the fist exert?

F= ?
m= .70 kg a= 3500 m/s2 F= .70 kg x 3500 m/s2 F= 2450 N 

weight

doesn't equal mass
force of gravity between object and large body (planet) depends on location measured w/ scale and Newtons 

mass

amount of matter
measured in kilograms constant everywhere 

weight formula

weight= mass x gravity
W= m x g 

acceleration due to gravity

9.8 m/s2


unit for weight

Newton


unit for gravity

m/s2


what is the mass of a 400 N rock?

m=?
W= 400 N g= 9.8 m/s2 400 N= m x 9.8m/s   9.8m/s2 9.8m/s2 m= 40.8 kg 

falling objects
(neglect air resistance) 
everything falls at same rate of acceleration on earth (9.8 m/s2)


falling objects
(w/ air resistance) 
fluid friction= force that opposes motin
depends on size, shape, speed (more speed, more air resistance) eventually force of gravity equals air resistance (terminal velocity) 

falling objects formula

distance = 1/2 gravity x time squared
d= 1/2gt2 

projectile motion
horizontal throwing 
v= d/t


projectile motion
dropping something 
a= final velocity  initial velocity
 time or d= 1/2gt2 

Newton's 3rd Law of Motion

forces always come in pairs (ActionReaction Pair)
when an object exerts a force on another object, then the 2nd object exerts the same size force in the opposite direction on the first object 

centripetal force

causes circular motion
always directed towards center of circle 

centrifugal force

no such thing


centripetal acceleration

acceleration towards the center of a circular path


momentum formula

momentum= mass x velocity
p=m x v 

law of conversation of momentum

momentum before a collision is equal to momentum after a collision


work

force applied over a distance in the same direction


work formula

Work= force x distance


power

how fast work is done


power formula

power= work
 time 

work formula

Work= force x distance


power

how fast work is done


power formula

power= work
 time 

unit for work

joule


unit for power

watt


1 hp= ?

550 ftlb
 s and 746 watts 

energy

ability to do work or to create a change in itself or its surroundings


5 types of energy

mechanical
chemical electromagnetic thermal nuclear 

kinetic energy

energy in form of motion of object


kinetic energy formula

KE = 1/2mv2


potential energy

energy due to objects position/condition (edge/stretched)


potential energy formula

PE= m x g x h


units for kinetic and potential energy

joule
