# Shared Flashcard Set

## Details

Physics UNIT 1
Measurment, Vectors, 1-D Motion
22
Physics
09/18/2011

Term
 Define and give units of speed
Definition
 speed is how fast, distance/time, units m/s or cm/s
Term
 Define and give units of instantaneous speed, velocity, acceleration
Definition
 its the speed, velocity, or acceleration at an insant, units still m/s, m/s, and m/s^2
Term
 Define and give units of velocity
Definition
 it is how fast with direction, vector quantity, units m/s
Term
 Define and give units of acceleration
Definition
 its the change in velocity/change in time, units m/s^2
Term
 Define and give units of distance
Definition
 speedxtime, scalar quantity, units m
Term
 Define and give units of displacement
Definition
 how far relative to a starting position, change in x, units m
Term
 Define and give units of density
Definition
 mass/volume, units kg/m^3
Term
 describe the physics of a set of keys thrown straight upward
Definition
 the keys are thrown up with an initial velocity, the gravitational force (acceleration due to gravity) slows the keys down, where t-top=v(subnot)/g, then the keys speed back up as they fall down and strike the hand with the same speed that they left the hand.
Term
 How far objects move dropped from rest in free fall
Definition
 ∆y=v(subnot)t-1/2gt^2an object moves a distance ∆y in free fall, which is equal to the initial velocity times time subtracted from half of the the gravitational constant times time squared.
Term
 How fast objects move dropped from rest in free fall
Definition
 either equation v=v(subnot)-gt or v^2=v(subnot)^2-2g∆yBoth equations can determine how fast, the first equation is how fast in regards to initial velocity subtracted by the gravitational constant times timeThe second equation is the initial velocity squared subtracted by 2 times the graviational constant times ∆y
Term
 Compare and contrast scalars and vectors
Definition
 Both scalars and vectors are quantities with magnitude, but only vectors are quantities with magnitude and direction.
Term
 Examples of scalars and vectors
Definition
 Scalars= temp, speed, distance, massVectors= force, velocity, acceleration, displacement
Term
 What objects of a car cause acceleration?
Definition
 Gas pedal, brakes, steering wheel, tires, etc---all are accelerators because they change speed or direction Acceleration is a vector quantity
Term
 Speedomoter or velocitomer in the car's dashboard?
Definition
 Speedomoter because it only gives magnitude, not direction, scalar quantity
Term
 Define and give examples of proportional
Definition
 technique for comparing quantities, if quantity A increases, then quantity B also increasesdistance α timeamnount of water in the tub α time water runningCircumfrence α diameter
Term
 Define and give examples of inversely proportional
Definition
 if quantity A increases, then quantity B decreases at the same rateP α 1/VMoney in your acct α 1/checks you write
Term
 What kinematic parameters are changing when an ojbect is in free fall dropped from rest?
Definition
 Time, velocity, displacement, NOT Acceleration
Term
 Acceleration due to gravity
Definition
 Any free-falling object is falling under the influence of gravity. All free falling objects dropped from rest accelerate at 9.8m/s^2
Term
 A box has volume 75 cubic inches, convert to cubic meters and centimeters
Definition
 m^3=.0012cm^3=1229.03
Term
 Compare d=st and d=(1/2)gt^2
Definition
 first equation is scalar, finding distance only with magnitudesecond equation is finding distance with acceleration, which makes it a vector quantity
Term
 After 2 seconds, a freely falling objects will have a speed of ?? and have dropped ?? m
Definition
 v=v(subnot)-gt=0-(9.8)(2)=-19.6m/s∆y=v(subnot)t-1/2gt^2=(0)(2)-1/2(9.8)(2)^2=-17.6m
Term
 discuss the three kinematic formulas
Definition
 v=v(subnot)+at∆x=v(subnot)+1/2at^2v^2-v(subnot)2=2a∆xThe first equation come about by the defn of acceleration and can be used to solve for any of the variablesThe second equation is a substitution of v into a ∆x equation so that there is no v The third equation is a substitution into the previous equation for t so that there is no time variable
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