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36 Cards in this Set
- Front
- Back
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scalar
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physical quantity that has magnitude but no direction
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vector
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physical quantity with both magnitude and direction
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speed
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distance/time
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velocity (v)
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displacement/time
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acceleration
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change in velocity/time
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graph (displacement v. time)
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m= instantaneous velocity
upward m= (+) velocity downward m= (-) velocity straight line=velocity constant curved line=acceleration |
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graph (velocity v. time)
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m= instantaneous acceleration
upward m=positive acceleration downward m= negative acceleration straight line= constant acceleration curved line= changing acceleration area under curve= displacement total displacement= area above x-axis - area below x-axis total distance= area above + area below x-axis |
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projectile motion
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-vertical velocity dictates time of flight
-horizontal distance is the horizontal velocity x time -horizontal velocity= v0cos -vertical initial velocity= v0sin -v0sin= square root of 2gh - vertical acceleration= -10m/s2 -no horizontal acceleration -at terminal velocity acceleration is 0 |
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air resistance
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affected by large surface area, shape (smooth vs. irregular), and velocity
air resistance has less effect on a more massive object, but air resistance is still the same |
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inertia
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the tendency for an object to remain in its present state of motion
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weight
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w=mg; gravitational force that the object experiences
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center of mass
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single pt at which all the mass of the system is concentrated; pt where a single force can be applied and all pts accelerate equally
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Newton's 1st law
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an object in motion/ at rest stays in motion/rest unless acted upon by a net force
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Newton's 2nd Law
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F=ma
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Newton's 3rd law
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for every action there is an equal and opposite reaction
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normal force
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(Fn) force pushing back against gravity, always perpendicular to surface
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Equations for Inclined Plane
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Fn+Fw=mgsin
Fn=mgcos Fn for curved surface=mgcos + Fc Fc= mAc=mv^2/r Fc points to the middle |
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Friction
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caused by attractive molecules between contiguous surfaces, opposes motion between surfaces
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static friction (fs)
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force opposing motion when two contiguous surfaces are not moving
fs is less than or equal to the coefficient of static friction times the normal force |
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kinetic friction (fk)
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force resisting motion once the two contiguous surfaces are sliding relative to each other
fk is less than or equal to the coefficient of kinetic friction times the normal force |
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Hooke's Law
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F=-k time the change in x
yield point: past this point object will not regain original shape fracture point: past this point and object will break |
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Equilibrium
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no translational (straight line) or angular (rotational) acceleration
for any system in translational equilibrium, the upward forces equal the downward forces and the rightward forces equal the leftward forces |
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static equilibrium
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all velocities are zero
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dynamic equilibrium
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velocities are not zero, but all velocities are constant
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torque
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twisting force
T= Frsin f=force vector r=position vector |
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mechanical energy
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kinetic energy and potential energy of a macrosystem
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kinetic energy
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energy of motion
KE=1/2mv^2 |
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Potential energy
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energy of position
gravitational PE=mgh elastic PE= 1/2Kx^2 |
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law of conservation
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the energy of the universe remains constant since it is an isolated system
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work
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transfer of energy via force
w=Fdsin |
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heat
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transfer of energy by natural flow form a warmer body to a cooler body
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total energy transfer
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w= KE + PE
no frictional forces included |
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conservative force
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system moves from pt A to pt B and back and the total work done by the force is zero
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Law of conservation of Mechanical Energy
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when conservative forces are acting, the sum of the mechanical energies remains constant
KE1 + PE1= KE2 +PE2 0= KE + PE |
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nonconservative forces
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forces that change the mechanical energy of a system when they do work
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power
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rate of energy transfer in watts (J/s)
p= delta E/ time or work/ time |
